Expression of UDP-glucuronosyltransferase 1A4 in human placenta at term

Sex-specific effects of Bisphenol a on the signalling pathway of ESRRG in the human placenta

Bisphenol A (BPA) exposure during pregnancy is associated with low fetal weight, particularly in male fetuses. The expression of estrogen-related receptor gamma (ESRRG), a receptor for BPA in the human placenta, is reduced in fetal growth restriction. This study sought to explore whether ESRRG signaling mediates BPA-induced placental dysfunction and determine whether changes in the ESRRG signaling pathway are sex-specific. Placental villous explants from 18 normal term pregnancies were cultured with a range of BPA concentrations (1 nM–1 μM). Baseline BPA concentrations in the placental tissue used for explant culture ranged from 0.04 to 5.1 nM (average 2.3 ±1.9 nM; n = 6). Expression of ESRRG signaling pathway constituents and cell turnover were quantified. BPA (1 μM) increased ESRRG mRNA expression after 24 h in both sexes. ESRRG mRNA and protein expression was increased in female placentas treated with 1 μM BPA for 24 h but was decreased in male placentas treated with 1 nM or 1 μM for 48 h. Levels of 17β-hydroxysteroid dehydrogenase type 1 (HSD17B1) and placenta specific-1 (PLAC1), genes downstream of ESRRG, were also affected. HSD17B1 mRNA expression was increased in female placentas by 1 μM BPA; however, 1 nM BPA reduced HSD17B1 and PLAC1 expression in male placentas at 48 h. BPA treatment did not affect rates of proliferation, apoptosis, or syncytiotrophoblast differentiation in cultured villous explants. This study has demonstrated that BPA affects the ESRRG signaling pathway in a sex-specific manner in human placentas and a possible biological mechanism to explain the differential effects of BPA exposure on male and female fetuses observed in epidemiological studies.

Placental transport of parabens studied using an ex-vivo human perfusion model

INTRODUCTION

Parabens are a group of chemicals widely used as preservatives in daily consumer products such as cosmetics, food items, pharmaceuticals and household commodities. They have been broadly detected in human samples indicating a general human exposure, and concerns arose from their potential endocrine disrupting effect. Especially the exposure to parabens during pregnancy is concerning, as the time of fetal development is a particularly vulnerable period. The aim of this study was to investigate the transport and metabolism of four commonly used parabens: methyl-, ethyl-, propyl- and butylparaben (MeP, EtP, PrP and BuP) and the metabolite para-hydroxybenzoic acid (PHBA) across the human placenta.

METHODS

An ex-vivo human placental perfusion model was used. The test compounds were added in the maternal compartment (with initial concentrations of 1 mM or 0.1 mM). Placental transport was evaluated by fetal-maternal concentration ratios (FM-ratio), transport index (TI) and indicative permeability (IP).

RESULTS

Information about parabens kinetics was taken from 10 perfusions and PHBA from 7 perfusions. Paraben metabolism was not detected. The placental transport of MeP, EtP, PrP, BuP and PHBA revealed a transfer from maternal to fetal circulations with FM₁₂₀ of 0.86 ± 0.27 (MeP), 0.98 ± 0.28 (EtP), 1.00 ± 0.28 (PrP), 1.12 ± 0.59 (BuP) and 0.82 ± 0.37 (PHBA). The test substances accumulated in the perfused tissue in some degree. The average kinetic parameters FM-ratio, TI and IP were not different between chemicals.

DISCUSSION

The present study shows that the placenta barrier is permeable to all four parabens and the metabolite, which implies potential fetal exposure.

Comprehensive Measurements of Intrauterine and Postnatal Exposure to Lamotrigine

OBJECTIVE

The aim of this study was to measure and investigate correlations of lamotrigine concentrations in maternal as well as umbilical cord blood, amniotic fluid, and breast milk to account for the distribution of the drug.

METHODS

Concentrations of lamotrigine were measured in 19 mother-infant pairs at the time of delivery. To account for the penetration ratio into amniotic fluid, cord blood and breast milk, the concentration of lamotrigine in the particular environment was divided by the concentration in maternal serum. A no-intercept model was applied for associations between maternal serum concentrations, amniotic fluid, umbilical cord blood, and breast milk concentrations.

RESULTS

The mean daily dosage of lamotrigine was 351.32 mg (range 50-650 mg). We detected associations between maternal serum and amniotic fluid (β = 0.088, p < 0.001), as well as umbilical cord (β = 0.939, p < 0.001) and breast milk (β = 0.964, p < 0.001). The median penetration ratio into amniotic fluid, cord blood, and breast milk was 0.68, 0.92, and 0.77, respectively.

CONCLUSIONS

Lamotrigine concentrations in amniotic fluid, cord blood, and breast milk give evidence that the fetus/newborn is constantly exposed to lamotrigine. Maternal serum concentrations predicted exposure via amniotic fluid, umbilical cord, and breast milk. Data suggest that therapeutic drug monitoring can be recommended as part of the clinical routine in psychopharmacotherapy for pregnant or breastfeeding women.

The role of xenobiotic-metabolizing enzymes in the placenta: a growing research field

Introduction: The placenta is a temporary and unique organ that allows for the physical connection between a mother and fetus; this organ regulates the transport of gases and nutrients mediating the elimination of waste products contained in the fetal circulation. The placenta performs metabolic and excretion functions, on the basis of multiple enzymatic systems responsible for the oxidation, reduction, hydrolysis, and conjugation of xenobiotics. These mechanisms give the placenta a protective role that limits the fetal exposure to harmful compounds. During pregnancy, some diseases require uninterrupted treatment even if it is detrimental to the fetus. Drugs and other xenobiotics alter gene expression in the placenta with repercussions for the fetus and mother's well-being.Areas covered: This review provides a brief description of the human placental structure and function, the main drug and xenobiotic transporters and metabolizing enzymes, placenta-metabolized substrates, and alterations in gene expression that the exposure to xenobiotics may cause.Expert opinion: Research should be focused on the identification and validation of biological markers for the assessment of the harmful effects of some drugs in pregnancy, including the evaluation of polymorphisms and methylation patterns in chorionic villous samples and/or amniotic fluid.

Transfer and Metabolism of the Xenoestrogen Zearalenone in Human Perfused Placenta

BACKGROUND

Pregnancy is a sensitive condition during which adverse environmental exposures should be monitored thoroughly and minimized whenever possible. In particular, the hormone balance during gestation is delicate, and disturbance may cause acute or chronic long-term health effects. A potential endocrine disruption may be provoked by in utero exposure to xenoestrogens mimicking endogenous estrogens. The mycoestrogen zearalenone (ZEN), a toxic fungal secondary metabolite and mycotoxin found frequently in food and feed, constitutes a prominent example.

OBJECTIVES

We performed a comprehensive assessment of the transfer as well as phase I and phase II metabolism of ZEN at the human placental barrier.

METHODS

Human placentas were perfused with 1μM (318μg/L) ZEN for 6 h. Samples from the maternal and fetal compartment, placental tissue, and fetal plasma were analyzed by a highly sensitive UHPLC-MS/MS assay to detect ZEN as well as nine key metabolites (α-zearalenol, β-zearalenol, zearalanone, α-zearalanol, β-zearalanol, ZEN-14-glucuronide, α-zearalenol-14-glucuronide, β-zearalenol-14-glucuronide, ZEN-14-sulfate).

RESULTS

The model revealed a fast maternofetal transfer of ZEN across the human placental barrier. We also unraveled phase I and phase II metabolism of the parent toxin ZEN into the approximately 70-times more estrogenic α-zearalenol and the less active ZEN-14-sulfate conjugate, which are effectively released into the maternal and fetal circulation in considerable amounts.

CONCLUSIONS

Our findings suggest that exposure to ZEN (such as through consumption of ZEN-contaminated cereal-based products) during pregnancy may result in in utero exposure of the fetus, not only to ZEN but also some of its highly estrogenically active metabolites. In the light of the known affinity of ZEN and potentially co-occurring xenoestrogens to the estrogen receptor, and our results demonstrating placental transfer of ZEN and its metabolites in an ex vivo model, we recommend further research and more comprehensive assessment of gestational exposures in women. https://doi.org/10.1289/EHP4860.

Normal pregnancy induced glucose metabolic stress in a longitudinal cohort of healthy women: Novel insights generated from a urine metabolomics study

During normal pregnancy, mothers face a unique physiological challenge in the adaptation of glucose metabolism in preparation for the metabolic stress presented by fetal development. However, the responsible mechanism remains elusive. The purpose of this study is to investigate the mechanism of the metabolic stress of glucose metabolism in pregnant women using metabolomics method.A Ultra Performance Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometer-based untargeted metabolomics study was performed to investigate the dynamic urinary signature of the intermediates of glucose metabolism in a longitudinal cohort of 232 healthy pregnant women in their first, second, and third trimesters.Twelve glucose metabolic intermediates were screened out from hundreds of candidate metabolites using partial least squares discriminant analysis models. These 12 markers were mainly involved in the metabolic pathways of insulin resistance, glycolysis/gluconeogenesis, tricarboxylic acid cycle, nonabsorbable carbohydrate metabolism, and N-glycan biosynthesis. In particular, L-acetylcarnitine, a metabolite that is beneficial for the amelioration of insulin resistance, decreased in a time-dependent manner during normal pregnancy. Moreover, thiamine pyrophosphate, an intermediate product of glycolysis/gluconeogenesis, significantly increased in the second trimester, and argininosuccinic acid and oxalosuccinic acid, intermediates involved in the tricarboxylic acid cycle, significantly decreased in the third trimester, suggesting an increased glucose demand in the maternal body during fetal development.These findings provide novel insight into the normal pregnancy-induced elevation of insulin resistance and glycolysis/gluconeogenesis, as well as the observed reduction in the aerobic oxidation of glucose.

Pregnancy exposure to quetiapine - Therapeutic drug monitoring in maternal blood, amniotic fluid and cord blood and obstetrical outcomes

RATIONALE

This prospective study is the first to measure and correlate quetiapine concentrations in maternal blood, amniotic fluid and umbilical cord blood to account for the distribution of quetiapine.

METHODS

Concentrations of quetiapine are quantified in seven mother infant pairs at the time of delivery. Data are provided as median values, first (Q1) and third (Q3) quartiles and ranges. To account for the penetration ratio, the concentration of quetiapine in amniotic fluid and cord blood was divided by maternal concentrations. Correlations between daily dosage, maternal serum and umbilical cord blood concentrations were computed for seven patients while calculations for amniotic fluid were only available for six mother-infant pairs.

RESULTS

The median daily dosage of quetiapine was 300mg (Q1: 300mg, Q3: 600mg, range 200-800mg). There was a strong and significant correlation between maternal serum and cord blood concentrations (r=0.893, p=0.007). The median penetration ratio into fetal circulation was 0.18 (Q1: 0.16, Q3: 0.32; range 0.13-0.42), suggesting a low penetration. The median penetration ratio into amniotic fluid was 0.44 (Q1: 0.15, Q3: 0.96; range 0.09-1.70).

CONCLUSIONS

Quetiapine concentrations in amniotic fluid and cord blood give evidence that quetiapine is constantly accessible to the fetus with a relatively low penetration ratio. A high correlation between maternal serum and umbilical cord blood concentrations highlights a predictive role of quantifying drug concentrations in maternal serum for assessing drug concentrations in fetal circulation. Findings support the important role of therapeutic drug monitoring in supporting the efficacy and safety of psychopharmacological treatment strategies in highly vulnerable populations.

Pregnancy exposure to citalopram - Therapeutic drug monitoring in maternal blood, amniotic fluid and cord blood

RATIONALE

Aim of the study was to measure and correlate citalopram concentrations in maternal blood, amniotic fluid and umbilical cord blood to account for the distribution of the drug between these three compartments.

METHODS

Concentrations of citalopram were measured in twelve mother infant pairs at the time of delivery. Data are provided as median values, first (Q1) and third (Q3) quartiles as well as ranges. To account for the penetration ratio into amniotic fluid and cord blood, the concentration of citalopram in was divided by the concentration in maternal serum. Correlations between daily dosage, maternal serum concentrations and umbilical cord blood concentrations were computed for twelve patients. As amniotic fluid was only available for nine mother infant pairs, appropriate calculations are provided for these mother-infant pairs.

RESULTS

The median daily dosage of citalopram was 20mg (Q1: 10mg, Q3: 20mg; range 10-40mg). The relation between the daily dosage of citalopram and its concentrations in maternal serum was highly significant (r=0.667, p=0.018). Maternal serum concentrations and cord blood concentrations were positively correlated (r=0.790, p=0.002) with a median penetration ratio into the fetal circulation of 0.78 (Q1: 0.52, Q3: 1.16, range 0.46-1.66). The median penetration ratio into amniotic fluid was 1.8 (Q1: 1.07, Q3: 2.64; range 0.52-6.97).

CONCLUSIONS

Citalopram concentrations in amniotic fluid and cord blood give evidence that maternally administered citalopram is constantly accessible to the fetus via amniotic fluid. A high correlation between maternal serum concentrations of citalopram and umbilical cord blood concentrations highlights a predictive role of quantifying drug concentrations in maternal serum for assessing drug concentrations in the fetal circulation. Findings support the important role of therapeutic drug monitoring in maintaining the safety of pregnant women and exposed infants.

Placental control of drug delivery

The placenta serves as the interface between the maternal and fetal circulations and regulates the transfer of oxygen, nutrients, and waste products. When exogenous substances are present in the maternal bloodstream-whether from environmental contact, occupational exposure, medication, or drug abuse-the extent to which this exposure affects the fetus is determined by transport and biotransformation processes in the placental barrier. Advances in drug delivery strategies are expected to improve the treatment of maternal and fetal diseases encountered during pregnancy.

Sertraline in pregnancy - Therapeutic drug monitoring in maternal blood, amniotic fluid and cord blood

RATIONALE

This study is the first to measure and correlate sertraline concentrations in maternal blood, amniotic fluid and umbilical cord blood and account for distribution of the drug between these three compartments.

METHODS

Concentrations of sertraline were measured in six mother infant pairs at the time of delivery. Data are provided as median values, first and third quartiles as well as ranges. To account for the penetration ratio into amniotic fluid and cord blood, the concentration of sertraline in both environments was divided by the concentration in maternal serum. Daily doses were correlated with maternal serum- and umbilical cord blood-concentrations, and serum levels were correlated with levels in amniotic fluid.

RESULTS

The median daily dose of sertraline was 75mg (Q1: 43.75mg, Q3: 100mg; range 25-100mg). Amniotic fluid concentrations of sertraline strongly correlated with the daily dose (r=0.833, p=0.039) while neither maternal serum concentrations nor cord blood concentrations correlated with the daily dose (p>0.05). The median penetration ratio for sertraline into amniotic fluid was 0.57 (Q1: 0.28, Q3: 0.75; range: 0.22-0.88). The median penetration ratio into the fetal circulation, calculated on the basis of umbilical cord blood-concentrations, was found to be 0.36 (Q1: 0.28, Q3: 0.49; range: 0.17-0.65).

CONCLUSIONS

Sertraline concentrations in amniotic fluid gave evidence that maternally administered sertraline is constantly accessible to the fetus via amniotic fluid in a manner not previously appreciated. A relatively low penetration into fetal circulation may contribute to a sufficient safety profile of sertraline during pregnancy although in our study APGAR Scores were relatively low in three infants. Our data support the important role of therapeutic drug monitoring in maintaining the safety of pregnant women and exposed infants.

Lamotrigine in pregnancy - therapeutic drug monitoring in maternal blood, amniotic fluid, and cord blood

This study is the first to measure and correlate lamotrigine concentrations in maternal blood, amniotic fluid, and umbilical cord blood and account for distribution of the drug between these three compartments. Concentrations of lamotrigine were measured in six mother-infant pairs at the time of delivery. Daily doses of lamotrigine ranged between 200 and 650 mg. Daily doses were correlated with maternal serum and umbilical cord blood concentrations, and serum levels were correlated with levels in amniotic fluid. Lamotrigine levels in serum correlated strongly with the lamotrigine levels in amniotic fluid (r=+0.986, P<0.001) and cord blood (r=+0.928, P=0.008). The penetration ratio into amniotic fluid was in a range between 0.31 and 0.75 (mean 0.58, SD 0.17); the penetration ratio into the fetal circulation, calculated on the basis of umbilical cord blood levels, was found to be in a range between 0.48 and 1.27 (mean 0.81, SD 0.28). Lamotrigine concentrations in amniotic fluid provided evidence that maternally administered lamotrigine is accessible to the fetus in a manner not previously appreciated. Furthermore, the penetration ratio into umbilical cord blood calculated here is in line with the largest study carried out so far to explore transplacental transfer.

Placental profiling of UGT1A enzyme expression and activity and interactions with preeclampsia at term

Placental UDP-glucuronosyltransferase (UGT) enzymes have critical roles in hormone, nutrient, chemical balance and fetal exposure during pregnancy. Placental UGT1A isoforms were profiled and differences between preeclamptic (PE) and non-PE placental UGT expression determined. In third trimester villous placenta, UGT1A1, 1A4, 1A6 and 1A9 were expressed and active in all specimens (n = 10), but UGT1A3, 1A5, 1A7, 1A8 and 1A10 were absent. The UGT1A activities were comparable to human liver microsomes per milligram, but placental microsome yields were only 2 % of liver (1 mg/g of tissue vs. 45 mg/g of tissue). For successful PCR, placental collection and processing within 60 min from delivery, including DNAse and ≥300 ng of RNA in reverse transcription were essential and snap freezing in liquid nitrogen immediately was the best preservation method. Although UGT1A6 mRNA was lower in PE (P < 0.001), there were no other significant effects on UGT mRNA, protein or activities. A more comprehensive tissue sample set is required for confirmation of PE interactions with UGT. Placental UGT1A enzyme expression patterns are similar to the liver and a detoxicative role for placental UGT1A is inferred.

Pregnancy and pharmacogenomics in the context of drug metabolism and response

It is well-known that profound physiological and biochemical changes occur throughout the course of pregnancy. At the same time, the role of pharmacogenomics in modulating the metabolism and response profile to numerous medications has been elucidated. Yet, the clinical impact of pharmacogenomics during pregnancy is less well understood. We present an overview of factors modulating the pharmacokinetics and pharmacodynamics of medications throughout the time span of pregnancy while providing insights on how pharmacogenomics may contribute to interindividual variability in drug metabolism and response amongst pregnant women.

MODEL-BASED LAMOTRIGINE CLEARANCE CHANGES DURING PREGNANCY: CLINICAL IMPLICATION

Objective

The objective of the study was to characterize changes in the oral clearance (CL/F) of lamotrigine (LTG) over the course of pregnancy and the postpartum period through a model-based approach incorporating clinical characteristics that may influence CL/F, in support of developing clinical management guidelines.

Methods

Women receiving LTG therapy who were pregnant or planning pregnancy were enrolled. Maternal blood samples were collected at each visit. A pharmacokinetic analysis was performed using a population-based, nonlinear, mixed-effects model.

Results

A total of 600 LTG concentrations from 60 women (64 pregnancies) were included. The baseline LTG CL/F was 2.16 L/h with a between-subject variability of 40.6%. The influence of pregnancy on CL/F was described by gestational week. Two subpopulations of women emerged based on the rate of increase in LTG CL/F during pregnancy. The gestational age-associated increase in CL/F displayed a 10-fold higher rate in 77% of the women (0.118 L/h per week) compared to 23% (0.0115 L/h per week). The between-subject variability in these slopes was 43.0%. The increased CL/F at delivery declined to baseline values with a half-life of 0.55 weeks.

Interpretation

The majority of women had a substantial increase in CL/F from 2.16 to 6.88 L/h by the end of pregnancy, whereas 23% of women had a minimal increase. An increase in CL/F may correspond to decreases in LTG blood concentrations necessitating the need for more frequent dosage adjustments and closer monitoring in some pregnant women with epilepsy. Postpartum doses should be tapered to preconception dose ranges within 3 weeks of delivery.

Upregulation of Ugt1a genes in placentas and fetal livers in a murine model of assisted reproduction

Genes from Ugt1a family in placenta and fetal liver are responsible for hormone, nutrient and chemical balance during pregnancy. Assisted reproduction technologies (ART) i.e. intracytoplasmic sperm injection (ICSI) and in vitro fertilization (IVF) alter steroid homeostasis in pregnancy through increased glucuronidation. Here we show that ART (particularly ICSI) upregulates Ugt1a1, 1a2, 1a6 and 1a9 expression in murine placentas and fetal livers with higher mRNA related to lower progesterone (1a1) and cholesterol (1a2, 1a6) in placentas. Greater steroid clearance in ART through transcriptional upregulation of Ugt1a in the placental-fetal unit may decrease the availability of essential molecules, mediating negative reproductive outcomes.