Placental phenotypes of intrauterine growth

The "toxic window" of amoxicillin exposure during pregnancy on long bone development in fetal mice

AIMS

Amoxicillin is a broad-spectrum beta-lactam antibiotic used to treat infectious diseases in pregnant women. Studies have shown that prenatal amoxicillin exposure (PAmE) has developmental toxicity on fetal development. However, the effect of PAmE on long bone development has not been reported. This study aimed to investigate the "toxic window" of PAmE on long bone development and explore its possible mechanism in fetal mice.

MATERIALS AND METHODS

Pregnant mice were administered amoxicillin by gavage at different stages (gestational day (GD)10-12 and GD16-18), different doses (150 and 300 mg/kg·d) and different courses (single and multiple courses). Fetal femurs were collected at GD18 and bone development related indicators were detected.

KEY FINDINGS

The results showed that PAmE significantly reduced the length of the femur and primary ossification center of fetal mice, and inhibited the development of fetal growth plate. Meanwhile, PAmE inhibited the development of bone marrow mesenchymal stem cells, osteoclasts and endothelial cells in fetal long bone. Further, we found the fetal long bone developmental toxicity induced by PAmE was most significant at late-pregnancy (GD16-18), high dose (300 mg/kg·d) and multiple-course group. Besides, PAmE inhibited the expression of Wnt/β-catenin signaling pathway in fetal long bone. The β-catenin mRNA expression was significantly positively correlated with the development indexes of fetal long bone.

SIGNIFICANCE

PAmE has toxic effects on long bone development, and there was an obvious "toxic window" of PAmE on the long bone development in fetal mice. The Wnt/β-catenin signaling pathway may mediate PAmE-induced fetal long bone development inhibition.

Dysregulation of miRNA-mRNA expression in fetal growth restriction in a caloric restricted mouse model

Fetal growth restriction (FGR) is associated with aberrant placentation and accounts for a significant proportion of perinatal deaths. microRNAs have been shown to be dysregulated in FGR. The purpose of this study was to determine microRNA-regulated molecular pathways altered using a caloric restricted mouse model of FGR. Pregnant mice were subjected to a 50% caloric restricted diet beginning at E9. At E18.5, RNA sequencing of placental tissue was performed to identify differences in gene expression between caloric restricted and control placentas. Significant differences in gene expression between caloric restricted and control placentas were observed in 228 of the 1546 (14.7%) microRNAs. Functional analysis of microRNA-mRNA interactions demonstrated enrichment of several biological pathways with oxidative stress, apoptosis, and autophagy pathways upregulated and angiogenesis and signal transduction pathways downregulated. Ingenuity pathway analysis also suggested that ID1 signaling, a pathway integral for trophoblast differentiation, is also dysregulated in caloric restricted placentas. Thus, a maternal caloric restriction mouse model of FGR results in aberrant microRNA-regulated molecular pathways associated with angiogenesis, oxidative stress, signal transduction, apoptosis, and cell differentiation. As several of these pathways are dysregulated in human FGR, our findings suggest that this model may provide an excellent means to study placental microRNA derangements seen in FGR.

A "toxic window" study on the hippocampal development of mice offspring exposed to azithromycin at different doses, courses, and time during pregnancy

BACKGROUND

Azithromycin, one of the new-generation macrolides, is an effective medicine for the treatment of mycoplasma infection during pregnancy. Epidemiological studies have reported adverse pregnancy outcomes with prenatal azithromycin exposure (PAzE). However, the effect of PAzE on fetal hippocampal development is unclear. This study aimed to explore the effects and potential mechanism of PAzE-induced fetal hippocampal development at different doses, courses, and time.

METHOD

Pregnant mice were administered azithromycin by gavage at different doses (50, 100 or 200 mg/kg.d), different courses (gestational day (GD)15-17 for three consecutive days, or GD17 once a day) and different time (GD10-12, GD15-17).

RESULTS

Compared with the control group, morphological development damage of the fetal hippocampus was observed in the PAzE group, with a dysbalance in neuronal proliferation and apoptosis, decreased expression of the neuronal-specific marker Snap25, NeuN, PSD95 and Map2, increased expression of the glial-specific marker Iba1, GFAP, and S-100β, and decreased expression of P2ry12. The PAzE-induced hippocampal developmental deficiency varied based on different doses, courses, and time, and the developmental toxicity was most significant in the late pregnancy, high dose, multi-course group (AZHT). The significant reduction of SOX2 and Wnt, which were related to regulation of neural progenitor cells (NPCs) proliferation in PAzE fetus compared with the control group indicated that the SOX2/Wnt signaling may be involved in PAzE-induced hippocampal developmental toxicity.

CONCLUSION

In this study, PAzE was associated with hippocampal developmental toxicity in a variety of nerve cells. Hippocampal developmental toxicity due to azithromycin was most significant in the late pregnancy, high-dose (equivalent to maximum clinical dose) and multi-course group (AZHT). The findings provide an experimental and theoretical foundation for guiding the sensible use of medications during pregnancy and effectively assessing the risk of fetal hippocampal developmental toxicity.

Comparison of nutrient supply from the dam to fetus and placental development in Holstein and Japanese black cows pregnant with similar or different fetus breeds

A lower nutrient supply from Holstein (HOL) dams to beef fetuses than HOL fetuses has been demonstrated, but the underlying factors remain unclear. We investigated maternal, umbilical vein, and calf blood glucose and amino acid concentrations at calving, along with placental development at term, in HOL dams with similar fetuses (HOL-HOL, n = 12), F1 crosses (HOL × Japanese Black [JB]; HOL-F1, n = 4), JB fetuses (HOL-JB, n = 7), and JB dams with similar fetuses (JB-JB, n = 11). Calf birth weight, total cotyledonary weight, and surface area were greater in HOL-HOL compared to JB-JB or HOL-JB (P < 0.05), whereas those of HOL-F1 were similar. Blood amino acid concentrations in the umbilical veins and calves were similar among HOL-HOL, HOL-F1, and HOL-JB. Calf blood glucose concentrations were lower in HOL-F1 than HOL-HOL (P < 0.05), despite similar maternal blood glucose levels. HOL-JB exhibited higher maternal, umbilical vein, and calf blood glucose concentrations than JB-JB (P < 0.05). Therefore, the glucose supply to the fetus may be inhibited in HOL-F1 due to maternal-fetal breed differences. Higher maternal blood glucose concentrations in HOL-JB may result in elevated fetal glucose exposure, potentially affecting postnatal growth and metabolism.

Dietary rumen-protected L-arginine or N-carbamylglutamate enhances placental amino acid transport and suppresses angiogenesis and steroid anabolism in underfed pregnant ewes

This study aimed to investigate the effects of dietary supplementation of underfed Hu ewes from d 35 to 110 of gestation with either rumen-protected L-arginine (RP-Arg) or N-carbamylglutamate (NCG) on placental amino acid (AA) transport, angiogenic gene expression, and steroid anabolism. On d 35 of gestation, 32 Hu ewes carrying twin fetuses were randomly divided into four treatment groups, each consisting of eight ewes, and were fed the following diets: A diet providing 100% of NRC's nutrient requirements for pregnant ewes (CON); A diet providing 50% of NRC's nutrient requirements for pregnant ewes (RES); RES diet plus 5 g/d NCG (RES + NCG); or RES diet plus 20 g/d RP-Arg (RES + ARG). On the d 110 of pregnancy, blood samples were taken from the mother, and samples were collected from type A cotyledons (COT; the fetal portions of the placenta). The levels of 17β-estradiol and progesterone in the maternal serum and both the capillary area density (CAD) and capillary surface density (CSD) in type A COT were decreased in response to Arg or NCG supplementation when compared to the RES group. The concentrations of arginine, leucine, putrescine and spermidine in type A COT were higher (P < 0.05) in the RES + ARG or RES + NCG group than in the RES group. The mRNA expression levels of inducible nitric oxide synthase (iNOS) and solute carrier family 15, member 1 (SLC15A1) were increased (P < 0.05) while those of progesterone receptor (PGR) and fibroblast growth factor 2 (FGF2) were decreased in type A COT by supplementation with either NCG or RP-Arg compared to the RES group. The results suggest that providing underfed pregnant ewes from d 35 to 110 of gestation with a diet supplemented with NCG or RP-Arg improves placental AA transport, and reduces the expression of angiogenic growth factor genes and steroid anabolism, leading to better fetal development.

Prenatal exposure to corn oil, CMC-Na or DMSO affects physical development and multi-organ functions in fetal mice

Corn oil, sodium carboxymethyl cellulose (CMC-Na), and dimethyl sulfoxide (DMSO) are widely used as solvents or suspensions in animal experiments, but the effects of prenatal exposure to them on fetal development have not been reported. In this study, Kunming mice were given a conventional dose of corn oil (9.2g/kg·d), CMC-Na (0.05g/kg·d) or DMSO (0.088g/kg·d) during gestation days 10-18, and the pregnancy outcome, fetal physical development, serum phenotype, and multi-organ function changes were observed. The results showed that corn oil decreased serum triglyceride level in males but increased their serum testosterone and CORT levels, and affected female placenta and female/male multi-organ functions (mainly bone, liver, kidney). CMC-Na increased female/male body lengths and tail lengths, decreased serum glucose and total cholesterol levels in males as well as increased their serum LDL-C/HDL-C ratio and testosterone level, decreased female serum bile acid level, and affected male/female placenta and multi-organ functions (mainly bone, liver, hippocampus). DMSO decreased male body weight and serum glucose level, decreased male/female serum bile acid levels, and affected male/female placenta and multi-organs functions (mainly bone, hippocampus, adrenal gland). In conclusion, prenatal exposure to a conventional dose of corn oil, CMC-Na or DMSO could affect fetal physical development and multi-organ functions, and has the characteristics of "multi-pathway, multi-organ and multi-target". This study provides the experimental basis for the rational selection of solvents or suspensions in pharmacology and toxicology studies. DATA AVAILABILITY: Data will be made available on request.

The Ethanolic Extract of Piper glabratum Kunth Is Teratogenic and Interferes with the Ossification Process of Swiss Mice Fetuses

Piper glabratum Kunth is a plant traditionally used to treat pain and inflammation in the Mato Grosso do Sul, Brazil. Even pregnant women consume this plant. Toxicology studies of the ethanolic extract from the leaves of P. glabratum (EEPg) could establish the safety of popular use of P. glabratrum. Thus, the effects of the ethanolic extract of leaves of P. glabratum (EEPg) on the reproductive performance and embryofetal development of Swiss mice were evaluated. Pregnant female mice were treated with 100, 1000 and 2000 mg/kg throughout the gestational period by gavage (p.o). The control group received the EEPg vehicle (Tween 80–1%) in the proportion of 0.1 mL/10 g (p.o.). The results demonstrated that EEPg has low maternal toxic potential and does not alter the reproductive performance of females. However, it altered embryofetal development and caused fetal weight reduction (increasing the frequency of small-for-gestational-age fetuses) at the two highest doses. In addition, it interfered with placental weight, placental index and placental efficiency. The frequency of visceral malformations increased by 2.8 times for the lowest dose of EEPg, and skeletal malformations increased by 2.48, 1.89 and 2.11 times for doses of 100, 1000 and 2000 mg/kg of EEPg, respectively. It is noteworthy that 100% of the offspring treated with EEPg showed changes in the ossification process. Thus, it is considered that the EEPg has low maternal toxic potential; it does not alter the reproductive performance of females. However, it is teratogenic and interferes, mainly, in the ossification process, and therefore its use is contraindicated in the gestational period.

Fetal growth restriction and neonatal-pediatric lung diseases: Vascular mechanistic links and therapeutic directions

Bronchopulmonary dysplasia (BPD) is the most common respiratory sequela of prematurity, and infants born with fetal growth restriction (FGR) are disproportionately represented in BPD statistics, as factors which affect somatic growth may also affect pulmonary growth. Effects of in-utero hypoxia underlying FGR on lung parenchymal architecture predisposing to BPD are well documented, but the pulmonary vascular constructs are not well appreciated. Disruption of angiogenesis during critical periods of lung growth impairs alveolarization, contributing to BPD pathogenesis. Pulmonary artery thickness/stiffness has been noted in FGR in the initial postnatal weeks, and also in well-grown infants with established BPD. The lack of waveform cushioning by the major arteries exposes the pulmonary resistance vessels to higher pulsatile stress, thereby accelerating microvascular disease. Reactive oxygen species, increased sympathetic activity and endothelial dysfunction are common mediators in FGR and BPD; each putative targets for prevention and/or therapeutics using interleukin (IL)-1 receptor antagonist (IL-1Ra), melatonin or inhibition of renin-angiotensin-aldosterone system. While BPD is the archetypal respiratory disease of infancy, effects of FGR on pulmonary function are long-term, extending well into childhood. This narrative links FGR in very/extremely preterm infants with BPD through the vascular affliction as a mechanistic and potentially, therapeutic pathway. Our objectives were to depict the burden of disease for FGR and BPD amongst preterm infants, portray vascular involvement in the placenta in FGR and BPD cohorts, provide high resolution vascular ultrasound information in both cohorts with a view to address therapeutic relevance, and lastly, link this information with paediatric age-group lung diseases.

The Ethanolic Extract of Gomphrena celosioides Mart. Does Not Alter Reproductive Performance or Embryo-Fetal Development, nor Does It Cause Chromosomal Damage

Gomphrena celosioides is a native Brazilian plant found in the State of Mato Grosso do Sul. It is used in folk medicine to treat kidney diseases, skin diseases, infections, rheumatism, gastrointestinal diseases, and respiratory diseases. It is also used as an abortifacient. To evaluate the effects of the ethanolic extract of Gomphrena celosioides (EEGc) on reproductive performance, embryo development, and chromosome stability, Swiss mice were randomly divided into experimental groups (n = 10). The animals in the control group received the vehicle Tween 80-1% in the proportion of 0.1 mL/10 g of body weight orally, from the first to the 18th gestational day. The animals in the treatment groups received the EEGc (100, 1000, and 2000 mg/kg) from the first to the 18th gestational day. The animals underwent evaluations of their reproductive performance and embryofetal development. The results showed that the EEGc did not change the animals' final weight, weight gain, uterine weight, or net weight gain. The evaluation showed that the absolute and relative organs' weights did not vary between the different experimental groups. In addition, the EEGc did not change the numbers of implants, live fetuses, dead fetuses, or fetal resorptions. There were no differences in post-operative loss rates, implantations, or resorptions, nor were there differences in fetal viability or sex ratio. The use of the EEGc did not result in different frequencies of malformations. In addition, the EEGc did not alter the frequency of chromosomal damage or frequency of micronuclei. Based on our findings, we considered the extract of Gomphrena celosioides to be safe for use during pregnancy, although some parameters indicated caution in its use.

Size-dependent placental retention effect of liposomes in ICR pregnant mice: Potential superiority in placenta-derived disease therapy

The great challenge in developing safe medications for placenta-derived diseases is to reduce or eliminate fetal drug exposure while still providing the necessary therapeutic effect. Rapid advances in nanotechnology have brought opportunities for the therapy of placenta-derived disease through accumulating the drug in the placenta while reducing its placental penetration. Among various nanocarriers, liposomes are regarded as an ideal type of carrier for placental drug delivery due to their biosafety and biodegradability. However, their placental retention effect with different particle sizes has not been studied. This research aimed to explore a suitable size of liposomes for placenta drug delivery. Cy 5 dye was chosen as a model molecule for tracing the distribution of three different-sized liposomes (∼80 nm, 200 nm, and 500 nm) in ICR pregnant mice. The stability, cytotoxicity, and cellular uptake study of Cy 5-loaded liposomes were performed. The in vivo fluorescence studies on ICR pregnant mice suggested that the particle size of liposomes was positively correlated with the degree of liposome aggregation in the placenta. The ratio of fluorescence in the placenta and fetus section (P/F value) was proposed to evaluate the placental retention effect of different-sized liposomes. The results showed that the liposomes with 500 nm had the highest P/F value and thus exhibited the strongest placental retention effect and the weakest placental penetration ability. Moreover, liquid chromatography-mass spectrometry analysis confirmed the reliability of the fluorescence section analysis in exploring the placental retention effect of nanovehicles. In general, this study introduced a simple and intuitive method to evaluate the placental retention effect of nanoplatforms and defined a suitable size of liposomes for placenta-derived disease drug delivery.

Ex vivo dual perfusion of an isolated human placenta cotyledon: Towards protocol standardization and improved inter-centre comparability

Since the full development of the ex vivo dual perfusion model of the human placenta cotyledon, the technique has provided essential insight into how nutrients, lipids, gases, immunoglobulins, endocrine agents, pharmaceuticals, chemicals, nanoparticles, micro-organisms and parasites might traverse the maternofetal barrier. Additionally, the model has been instrumental in gaining a better understanding of the regulation of vascular tone, endocrinology and metabolism within this organ. The human placenta is unique amongst species in its anatomy and transfer modalities. This orthologous diversity therefore requires an appropriate consideration of placental transfer rates of compounds, particles and micro-organisms specific to humans. Different research centres have adapted this model with a wide variation in perfusion parameters, including in the establishment of perfusion, perfusate composition, gassing regime, cannulation method, flow rates, perfused tissue mass, and also in the application of quality control measures. The requirement to harmonise and standardise perfusion practice between centres is largely driven by the need to obtain consistency in our understanding of placental function, but also in the qualification of the model for acceptance by regulatory agencies in drug and toxicology testing. A pilot study is proposed, aiming to describe how existing inter-centre variation in perfusion methodology affects placental metabolism, protein synthesis, oxygen consumption, the materno-fetal transfer of key molecular markers, and placental structure.

Maternal nutrient restriction and over-feeding during gestation alter expression of key factors involved in placental development and vascularization

Poor maternal nutrition can negatively affect fetal and placental growth and development. However, the mechanism(s) that contribute to altered placenta growth and function are not well understood. We hypothesized that poor maternal diet would impact signaling through the C-X-C motif chemokine ligand (CXCL) 12-CXCL4 axis and/or placental expression of the insulin-like growth factor (IGF) axis. Using our established sheep model of poor maternal nutrition, we examined the effects of restricted- and over-feeding on ewe placentome gene and protein expression. Specifically, ewes were fed a control (CON; 100%), restricted (RES; 60%), or over (OVER; 140%) diet beginning at day 30.2 ± 0.02 of gestation, and samples were collected at days 45, 90, and 135 of gestation, representing periods of active placentation, peak placental growth, and near term, respectively. Placentomes were separated into cotyledon and caruncle, and samples snap frozen. Protein was determined by western blot and mRNA expression by real-time PCR. Data were analyzed by ANOVA and significance determined at P ≤ 0.05. Ewes fed a RES diet had decreased CXCL12 and vascular endothelial growth factor (VEGF), and increased tumor necrosis factor (TNF)α protein compared with CON ewes in caruncle at day 45 (P ≤0.05). In day 45 cotyledon, CXCR7 protein was increased and mTOR was decreased in RES relative to CON (P ≤0.05). At day 90, CXCR4 and CXCR7 were reduced in RES caruncle compared with CON, whereas VEGF was reduced and mTOR increased in cotyledon of RES ewes relative to CON (P ≤0.05). In OVER caruncle, at day 45 CXCR4 and VEGF were reduced and at day 90 CXCR4, CXCR7, and TNFα were reduced in caruncle compared with CON (P ≤0.05). There was no observed effect of OVER diet on protein abundance in the cotyledon (P > 0.05). Expression of IGF-II mRNA was increased in OVER at day 45 and IGFBP-3 was reduced in RES at day 90 in caruncle relative to CON (P ≤0.05). Maternal diet did not alter placentome diameter or weight (P > 0.05). These findings suggest that restricted- and over-feeding negatively impact protein and mRNA expression of key chemokines and growth factors implicated in proper placenta development and function.

Perinatal and Neonatal Outcomes in Fetal Growth Restriction and Small for Gestational Age

Alterations in intrauterine fetal growth increase the risk of adverse perinatal and neonatal outcomes. In this retrospective study, we analyzed data of 906 pregnancies collected in our maternal fetal medicine center, with different patterns of growth: 655 AGA (Appropriate for Gestational Age), 62 SGA (Small for Gestational Age: fetuses born with a weight less than 10° centile, not diagnosed before delivery), 189 FGR (Fetal Growth Restriction, classified in early and late according to gestational week at diagnosis). For each group, we compared maternal characteristics, gestational age at delivery, and perinatal and neonatal outcomes. Risk factors for fetal growth alterations were advanced age, being primiparous, and a lower pregestational BMI. FGR fetuses were born at earlier gestational ages (32 [IQR 29-38] early-FGR and 38 [IQR 36-39] late-FGR), with blood gas values comparable to the AGA group but worse neonatal outcomes related to prematurity. Unexpected SGA fetuses born by vaginal delivery, managed as AGA, were more hyperlactacidemic (4.4 [IQR 2.7-5.5]) and hypoxemic (-5.0 [IQR -7.1-2.8]) at birth than both AGA and FGR. However, neonatal outcomes (accesses and days of hospitalization in NICU) were better than FGR, likely due to gestational age and birthweight similar to AGA.

Sexually dimorphic patterns in maternal circulating microRNAs in pregnancies complicated by fetal growth restriction

Background

Current methods fail to accurately predict women at greatest risk of developing fetal growth restriction (FGR) or related adverse outcomes, including stillbirth. Sexual dimorphism in these adverse pregnancy outcomes is well documented as are sex-specific differences in gene and protein expression in the placenta. Circulating maternal serum microRNAs (miRNAs) offer potential as biomarkers that may also be informative of underlying pathology. We hypothesised that FGR would be associated with an altered miRNA profile and would differ depending on fetal sex.

Methods

miRNA expression profiles were assessed in maternal serum (> 36 weeks’ gestation) from women delivering a severely FGR infant (defined as an individualised birthweight centile (IBC) < 3rd) and matched control participants (AGA; IBC = 20–80th), using miRNA arrays. qPCR was performed using specific miRNA primers in an expanded cohort of patients with IBC < 5th (n = 15 males, n = 16 females/group). Maternal serum human placental lactogen (hPL) was used as a proxy to determine if serum miRNAs were related to placental dysfunction. In silico analyses were performed to predict the potential functions of altered miRNAs.

Results

Initial analyses revealed 11 miRNAs were altered in maternal serum from FGR pregnancies. In silico analyses revealed all 11 altered miRNAs were located in a network of genes that regulate placental function. Subsequent analysis demonstrated four miRNAs showed sexually dimorphic patterns. miR-28-5p was reduced in FGR pregnancies (p < 0.01) only when there was a female offspring and miR-301a-3p was only reduced in FGR pregnancies with a male fetus (p < 0.05). miR-454-3p was decreased in FGR pregnancies (p < 0.05) regardless of fetal sex but was only positively correlated to hPL when the fetus was female. Conversely, miR-29c-3p was correlated to maternal hPL only when the fetus was male. Target genes for sexually dimorphic miRNAs reveal potential functional roles in the placenta including angiogenesis, placental growth, nutrient transport and apoptosis.

Conclusions

These studies have identified sexually dimorphic patterns for miRNAs in maternal serum in FGR. These miRNAs may have potential as non-invasive biomarkers for FGR and associated placental dysfunction. Further studies to determine if these miRNAs have potential functional roles in the placenta may provide greater understanding of the pathogenesis of placental dysfunction and the differing susceptibility of male and female fetuses to adverse in utero conditions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13293-021-00405-z.

Detection and treatment of pregnancies at high risk of fetal growth restriction (FGR) and stillbirth remains a major obstetric challenge; circulating maternal serum microRNAs (miRNAs) offer potential as novel biomarkers.

Unbiased analysis of serum miRNAs in women in late pregnancy identified a specific profile of circulating miRNAs in women with a growth-restricted infant.

Some altered miRNAs (miR-28-5p, miR-301a-3p) showed sexually dimorphic expression in FGR pregnancies and others a fetal-sex dependent association to a hormonal marker of placental dysfunction (miR-454-3p, miR-29c-3p).

miR-301a-3p and miR-28-5p could potentially be used to predict FGR specifically in pregnancies with a male or female baby, respectively, however larger cohort studies are required.

Further investigations of these miRNAs and their relationship to placental dysfunction will lead to a better understanding of the pathophysiology of FGR and why there is differing susceptibility of male and female fetuses to FGR and stillbirth.

Characterization of the Primary Human Trophoblast Cell Secretome Using Stable Isotope Labeling With Amino Acids in Cell Culture

The placental villus syncytiotrophoblast, the nutrient-transporting and hormone-producing epithelium of the human placenta, is a critical regulator of fetal development and maternal physiology. However, the identities of the proteins synthesized and secreted by primary human trophoblast (PHT) cells remain unknown. Stable Isotope Labeling with Amino Acids in Cell Culture followed by mass spectrometry analysis of the conditioned media was used to identify secreted proteins and obtain information about their relative rates of synthesis in syncytialized multinucleated PHT cells isolated from normal term placental villus tissue (n = 4/independent placenta). A total of 1,344 proteins were identified, most of which have not previously been reported to be secreted by the human placenta or trophoblast. The majority of secreted proteins are involved in energy and carbon metabolism, glycolysis, biosynthesis of amino acids, purine metabolism, and fatty acid degradation. Histone family proteins and mitochondrial proteins were among proteins with the slowest synthesis rate whereas proteins associated with signaling and the plasma membrane were synthesized rapidly. There was a significant overlap between the PHT secretome and proteins known be secreted to the fetal circulation by the human placenta in vivo. The generated data will guide future experiments to determine the function of individual secreted proteins and will help us better understand how the placenta controls maternal and fetal physiology.

Reduction of In Vivo Placental Amino Acid Transport Precedes the Development of Intrauterine Growth Restriction in the Non-Human Primate

Intrauterine growth restriction (IUGR) is associated with reduced placental amino acid transport (AAT). However, it remains to be established if changes in AAT contribute to restricted fetal growth. We hypothesized that reduced in vivo placental AAT precedes the development of IUGR in baboons with maternal nutrient restriction (MNR). Baboons were fed either a control (ad libitum) or MNR diet (70% of control diet) from gestational day (GD) 30. At GD 140, in vivo transplacental AA transport was measured by infusing nine ⁽¹³⁾C- or ⁽²⁾H-labeled essential amino acids (EAAs) as a bolus into the maternal circulation at cesarean section. A fetal vein-to-maternal artery mole percent excess ratio for each EAA was measured. Microvillous plasma membrane (MVM) system A and system L transport activity were determined. Fetal and placental weights were not significantly different between MNR and control. In vivo, the fetal vein-to-maternal artery mole percent excess ratio was significantly decreased for tryptophan in MNR. MVM system A and system L activity was markedly reduced in MNR. Reduction of in vivo placental amino acid transport precedes fetal growth restriction in the non-human primate, suggesting that reduced placental amino acid transfer may contribute to IUGR.

Altered Umbilical Cord Blood Nutrient Levels, Placental Cell Turnover and Transporter Expression in Human Term Pregnancies Conceived by Intracytoplasmic Sperm Injection (ICSI)

Assisted reproductive technologies (ART) may increase risk for abnormal placental development, preterm delivery and low birthweight. We investigated placental morphology, transporter expression and paired maternal/umbilical fasting blood nutrient levels in human term pregnancies conceived naturally (n = 10) or by intracytoplasmic sperm injection (ICSI; n = 11). Maternal and umbilical vein blood from singleton term (>37 weeks) C-section pregnancies were assessed for levels of free amino acids, glucose, free fatty acids (FFA), cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL), very low-density lipoprotein (VLDL) and triglycerides. We quantified placental expression of GLUT1 (glucose), SNAT2 (amino acids), P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) (drug) transporters, and placental morphology and pathology. Following ICSI, placental SNAT2 protein expression was downregulated and umbilical cord blood levels of citrulline were increased, while FFA levels were decreased at term (p < 0.05). Placental proliferation and apoptotic rates were increased in ICSI placentae (p < 0.05). No changes in maternal blood nutrient levels, placental GLUT1, P-gp and BCRP expression, or placental histopathology were observed. In term pregnancies, ICSI impairs placental SNAT2 transporter expression and cell turnover, and alters umbilical vein levels of specific nutrients without changing placental morphology. These may represent mechanisms through which ICSI impacts pregnancy outcomes and programs disease risk trajectories in offspring across the life course.

Maternal intermittent fasting during pregnancy induces fetal growth restriction and down-regulated placental system A amino acid transport in the rat

During Ramadan, many pregnant Muslim women fast between dawn and sunset. Although the impacts of prolonged maternal intermittent fasting (IF) on fetal growth and placental function are under-researched, reported effects include reduced placental weight and birth weight. In the present study, pregnant Wistar rats were used to model repeated cycles of IF on fetal development and placental function and to examine sex-specific effects. In the IF group, food was withdrawn daily from 17:00 to 09:00 over 21 days of gestation, while the control group received food ad libitum. Both groups had free water access. IF dams consumed less food, had significantly reduced weight compared with controls, with reduced plasma glucose and amino acids. Both fetal sexes were significantly lighter in the IF group with reduced fetal plasma amino acids. Placental weights and morphology were unchanged. The profile of placental metabolites was altered in the IF group with sex-specific responses evident. Transplacental flux of 14C-methylaminoisobutyric acid (14C-MeAIB), a system A amino acid transporter substrate, was significantly reduced in both fetal sexes in the IF group. Sodium-dependent 14C-MeAIB uptake into isolated placental plasma membrane vesicles was unchanged. The gene expression of system A transporter Slc38a1, Slc38a2 and Slc38a4 was up-regulated in IF male placentas only. No changes were observed in placental SNAT1 and SNAT2 protein expression. Maternal IF results in detrimental impacts on maternal physiology and fetal development with changes in the placental and fetal metabolite profiles. Reduced placental system A transporter activity may be responsible for fetal growth restriction in both sexes.

A Novel Review of Homocysteine and Pregnancy Complications

Homocysteine (Hct) is a substance produced in the metabolism of methionine. It is an essential type of amino acid gained from the daily diet. Methylenetetrahydrofolate reductase (MTHFR) gene mutation is related to elevated total homocysteine (tHct) expressions, in particular, among women with low folate intake. Hyperhomocysteinemia (HHct) is caused by numerous factors, such as genetic defects, lack of folic acid, vitamin B₆ and B₁₂ deficiency, hypothyroidism, drugs, aging, and renal dysfunction. Increased Hct in peripheral blood may lead to vascular illnesses, coronary artery dysfunction, atherosclerotic changes, and embolic diseases. Compared to nonpregnant women, the Hct level is lower in normal pregnancies. Recent studies have reported that HHct was associated with numerous pregnancy complications, including recurrent pregnancy loss (RPL), preeclampsia (PE), preterm delivery, placental abruption, fetal growth restriction (FGR), and gestational diabetes mellitus (GDM). Besides, it was discovered that neonatal birth weight and maternal Hct levels were negatively correlated. However, a number of these findings lack consistency. In this review, we summarized the metabolic process of Hct in the human body, the levels of Hct in different stages of normal pregnancy reported in previous studies, and the relationship between Hct and pregnancy complications. The work done is helpful for obstetricians to improve the likelihood of a positive outcome during pregnancy complications. Reducing the Hct level with a high dosage of folic acid supplements during the next pregnancy could be helpful for females who have suffered pregnancy complications due to HHct.

Hypoxia and oxidative stress induce sterile placental inflammation in vitro

Fetal growth restriction (FGR) and stillbirth are associated with placental dysfunction and inflammation and hypoxia, oxidative and nitrative stress are implicated in placental damage. Damage-associated molecular patterns (DAMPs) are elevated in pregnancies at increased risk of FGR and stillbirth and are associated with increase in pro-inflammatory placental cytokines. We hypothesised that placental insults lead to release of DAMPs, promoting placental inflammation. Placental tissue from uncomplicated pregnancies was exposed in vitro to hypoxia, oxidative or nitrative stress. Tissue production and release of DAMPs and cytokines was determined. Oxidative stress and hypoxia caused differential release of DAMPs including uric acid, HMGB1, S100A8, cell-free fetal DNA, S100A12 and HSP70. After oxidative stress pro-inflammatory cytokines (IL-1α, IL-1β, IL-6, IL-8, TNFα, CCL2) were increased both within explants and in conditioned culture medium. Hypoxia increased tissue IL-1α/β, IL-6, IL-8 and TNFα levels, and release of IL-1α, IL-6 and IL-8, whereas CCL2 and IL-10 were reduced. IL1 receptor antagonist (IL1Ra) treatment prevented hypoxia- and oxidative stress-induced IL-6 and IL-8 release. These findings provide evidence that relevant stressors induce a sterile inflammatory profile in placental tissue which can be partially blocked by IL1Ra suggesting this agent has translational potential to prevent placental inflammation evident in FGR and stillbirth.

Nanoparticles in pregnancy: the next frontier in reproductive therapeutics

BACKGROUND

Nanotechnology involves the engineering of structures on a molecular level. Nanomedicine and nano-delivery systems have been designed to deliver therapeutic agents to a target site or organ in a controlled manner, maximizing efficacy while minimizing off-target effects of the therapeutic agent administered. In both reproductive medicine and obstetrics, developing innovative therapeutics is often tempered by fears of damage to the gamete, embryo or developing foetus or of negatively impacting a woman's reproductive potential. Thus, nanomedicine delivery systems may provide alternative targeted intervention strategies, treating the source of the disease and minimizing long-term consequences for the mother and/or her foetus.

OBJECTIVE AND RATIONALE

This review summarizes the current state of nanomedicine technology in reproductive medicine and obstetrics, including safety, potential applications, future directions and the hurdles for translation.

SEARCH METHODS

A comprehensive electronic literature search of PubMed and Web of Science databases was performed to identify studies published in English up until February 2020. Relevant keywords were used to obtain information regarding use of nanoparticle technology in fertility and gene therapy, early pregnancy complications (ectopic pregnancy and gestational trophoblastic disease) and obstetric complications (preeclampsia, foetal growth restriction, preterm birth and gestational diabetes) and for selective treatment of the mother or foetus. Safety of specific nanoparticles to the gamete, embryo and foetus was also investigated.

OUTCOMES

Pre-clinical research in the development of nanoparticle therapeutic delivery is being undertaken in many fields of reproductive medicine. Non-hormonal-targeted nanoparticle therapy for fibroids and endometriosis may provide fertility-sparing medical management. Delivery of interventions via nanotechnology provides opportunities for gene manipulation and delivery in mammalian gametes. Targeting cytotoxic treatments to early pregnancy tissue provides an alternative approach to manage ectopic pregnancies and gestational trophoblastic disease. In pregnancy, nanotherapeutic delivery offers options to stably deliver silencing RNA and microRNA inhibitors to the placenta to regulate gene expression, opening doors to novel genetic treatments for preeclampsia and foetal growth restriction. Restricting delivery of teratogenic drugs to the maternal compartment (such as warfarin) may reduce risks to the foetus. Alternatively, targeted delivery of drugs to the foetus (such as those to treat foetal arrythmias) may minimize side effects for the mother.

WIDER IMPLICATIONS

We expect that further development of targeted therapies using nanoparticles in a reproductive setting has promise to eventually allow safe and directed treatments for conditions impacting the health and reproductive capacity of women and for the management of pregnancy and serious pregnancy complications.

Maternal Amino Acid Profiles to Distinguish Constitutionally Small versus Growth-Restricted Fetuses Defined by Doppler Ultrasound: A Pilot Study

OBJECTIVE

Fetuses measuring below the 10th percentile for gestational age may be either constitutionally small for gestational age (SGA) or have pathologic fetal growth restriction (FGR). FGR is associated with adverse outcomes; however, identification of low-risk SGA cases is difficult. We performed a pilot study evaluating maternal markers of pathologic FGR, hypothesizing there are distinct amino acid signatures that might be used for diagnosis and development of new interventions.

STUDY DESIGN

This was a cohort study of healthy women with sonographic fetal estimated fetal weight <5th percentile divided into two groups based upon umbilical artery (UmA) Doppler studies or uterine artery (UtA) Doppler studies. We collected maternal blood samples prior to delivery and used ion pair reverse phase liquid chromatography-mass spectrometry or gas chromatography-mass spectrometry to assess 44 amino acids.

RESULTS

Among 14 women included, five had abnormal UmA, and three had abnormal UtA Doppler results. Those with abnormal UmA showed elevated ornithine. Those with abnormal UtA had lower dimethylglycine, isoleucine, methionine, phenylalanine, and 1-methylhistidine.

CONCLUSION

We found several amino acids that might identify pregnancies affected by pathologic FGR. These findings support the feasibility of future larger studies to identify maternal metabolic approaches to accurately stratify risk for small fetuses.

Preserved efficiency of sickle cell disease placentas despite altered morphology and function

INTRODUCTION

Pregnant women with sickle cell disease (SCD) are at high risk for sickle cell-related complications, obstetrical complications, and perinatal morbidity. Chronic inflammation and the proangiogenic environment associated with SCD have been associated with endothelial damage. It is unknown whether SCD complications could be associated with placental dysfunction or abnormal placental morphology. Moreover, circulating angiogenic factors in pregnant women with SCD are unexplored.

METHODS

Clinical records, placental and blood samples were collected at term delivery for 21 pregnant patients with SCD and 19 HbAA pregnant controls with adapted to gestational age birth weight newborns. Histological and stereological analyses and scanning electron microscopy (SEM) of the placenta, and PlGF and sFlt1 measurements in blood were performed.

RESULTS

In the SCD group, the parenchyma-forming villi of placentas were thinner than in controls, and increased fibrinoid necrosis and an overabundance of syncytial knots were seen. SEM revealed elongated intermediate villous endings with a reduction in the number of terminal villi compared to controls, indicating a significant branching defect in SCD placentas. Finally, SCD patients had an imbalance in the angiogenic ratio of sFlt1/PlGF (p = 0.008) with a drop of PlGF concentrations.

DISCUSSION

We evidence for the first time both abnormal placenta morphology and altered sFlt1/PlGF ratio in SCD patients, uncorrelated with maintained placental efficiency and fetal growth.

Is small placenta a risk for low birth weight in KOKAN? (Data from a coastal region in the state of Maharashtra, India)

KOKAN region is characterized by undernutrition across all stages of lifecycle. Developmental Origins of Health & Disease hypothesis suggests that environmental influences in the early period of growth and development can contribute to the risks of noncommunicable diseases (NCD) in adulthood. Newborns and placentas of 815 pregnant mothers delivered in a rural hospital were studied. We tested the hypothesis that low placental weight will be associated with low birth weight (LBW). Mothers had a mean age of 26 years and were smaller in size at delivery [mean height of 152.1 cm (±6.1 cm), weight 52 kg (±10.2 kg), body mass index (BMI) 22.5 kg/m2 (±4.1 kg/m2)]. Mean placental weight was 488 g (±120 g). Mean birth weight, length, and head circumference of the newborn were 2.54 kg (±0.5 kg), 46.3 cm (±3.1 cm), and 32.7 cm (±1.7 cm), respectively. Prevalence of LBW, stunting, and small head size was 41.6%, 42.2%, and 18.2%, respectively. Maternal height, weight, and BMI at delivery were all positively associated with placental weight (p < 0.01 for all). Mothers with placentas in the lowest placental weight tertile had an increased likelihood of producing an LBW baby [OR 7.7, 95% CI (5.0, 11.8)], a stunted baby [OR 1.9 (1.4, 2.9)], or a baby with a small head circumference [OR 2.4 (1.4, 4.0)]. Mothers in the lowest height tertile had odds of producing a LBW baby [OR 1.8 95% CI (1.2, 2.7)] or a stunted baby [OR 1.6 (1.1, 2.3)]. There is a need to improve the nutritional status of women in KOKAN region which may reduce the risk of NCD.

The role of insulin-like growth factor 2 receptor-mediated homeobox gene expression in human placental apoptosis, and its implications in idiopathic fetal growth restriction

Fetal growth restriction (FGR) is caused by poor placental development and function early in gestation. It is well known that placentas from women with FGR exhibit reduced cell growth, elevated levels of apoptosis and perturbed expression of the growth factors, cytokines and the homeobox gene family of transcription factors. Previous studies have reported that insulin-like growth factor-2 (IGF2) interacts with its receptor-2 (IGF2R) to regulate villous trophoblast survival and apoptosis. In this study, we hypothesized that human placental IGF2R-mediated homeobox gene expression is altered in FGR and contributes to abnormal trophoblast function. This study was designed to determine the association between IGF2R, homeobox gene expression and cell survival in pregnancies affected by FGR. Third trimester placentas were collected from FGR-affected pregnancies (n = 29) and gestation matched with control pregnancies (n = 30). Functional analyses were then performed in vitro using term placental explants (n = 4) and BeWo trophoblast cells. mRNA expression was determined by real-time PCR, while protein expression was examined by immunoblotting and immunohistochemistry. siRNA transfection was used to silence IGF2R expression in placental explants and the BeWo cell-line. cDNA arrays were used to screen for downstream targets of IGF2R, specifically homeobox gene transcription factors and apoptosis-related genes. Functional effects of silencing IGF2R were then verified by β-hCG ELISA, caspase activity assays and a real-time electrical cell-impedance assay for differentiation, apoptosis and cell growth potential, respectively. IGF2R expression was significantly decreased in placentas from pregnancies complicated by idiopathic FGR (P < 0.05 versus control). siRNA-mediated IGF2R knockdown in term placental explants and the trophoblast cell line BeWo resulted in altered expression of homeobox gene transcription factors, including increased expression of distal-less homeobox gene 5 (DLX5), and decreased expression of H2.0-Like Homeobox 1 (HLX) (P < 0.05 versus control). Knockdown of IGF2R transcription increased the expression and activity of caspase-6 and caspase-8 in placental explants, decreased BeWo proliferation and increased BeWo differentiation (all P < 0.05 compared to respective controls). This is the first study linking IGF2R placental expression with changes in the expression of homeobox genes that control cellular signalling pathways responsible for increased trophoblast cell apoptosis, which is a characteristic feature of FGR.

Placental Microarray Profiling Reveals Common mRNA and lncRNA Expression Patterns in Preeclampsia and Intrauterine Growth Restriction

Preeclampsia (PE) and Intrauterine Growth Restriction (IUGR) are major contributors to perinatal morbidity and mortality. These pregnancy disorders are associated with placental dysfunction and share similar pathophysiological features. The aim of this study was to compare the placental gene expression profiles including mRNA and lncRNAs from pregnant women from four study groups: PE, IUGR, PE-IUGR, and normal pregnancy (NP). Gene expression microarray analysis was performed on placental tissue obtained at delivery and results were validated using RTq-PCR. Differential gene expression analysis revealed that the largest transcript variation was observed in the IUGR samples compared to NP (n = 461; 314 mRNAs: 252 up-regulated and 62 down-regulated; 133 lncRNAs: 36 up-regulated and 98 down-regulated). We also detected a group of differentially expressed transcripts shared between the PE and IUGR samples compared to NP (n = 39), including 9 lncRNAs with a high correlation degree (p < 0.05). Functional enrichment of these shared transcripts showed that cytokine signaling pathways, protein modification, and regulation of JAK-STAT cascade are over-represented in both placental ischemic diseases. These findings contribute to the molecular characterization of placental ischemia showing common epigenetic regulation implicated in the pathophysiology of PE and IUGR.

The placenta in fetal growth restriction: What is going wrong?

The placenta is essential for the efficient delivery of nutrients and oxygen from mother to fetus to maintain normal fetal growth. Dysfunctional placental development underpins many pregnancy complications, including fetal growth restriction (FGR) a condition in which the fetus does not reach its growth potential. The FGR placenta is smaller than normal placentae throughout gestation and displays maldevelopment of both the placental villi and the fetal vasculature within these villi. Specialized epithelial cells called trophoblasts exhibit abnormal function and development in FGR placentae. This includes an altered balance between proliferation and apoptotic death, premature cellular senescence, and reduced colonisation of the maternal decidual tissue. Thus, the placenta undergoes aberrant changes at the macroscopic to cellular level in FGR, which can limit exchange capacity and downstream fetal growth. This review aims to compile stereological, in vitro, and imaging data to create a holistic overview of the FGR placenta and its pathophysiology, with a focus on the contribution of trophoblasts.

Adaptive responses to maternal nutrient restriction alter placental transport in ewes

INTRODUCTION

Maternal nutrient partitioning, uteroplacental blood flow, transporter activity, and fetoplacental metabolism mediate nutrient delivery to the fetus. Inadequate availability or delivery of nutrients results in intrauterine growth restriction (IUGR), a leading cause of neonatal morbidity and mortality. Maternal nutrient restriction can result in IUGR, but only in an unforeseeable subset of individuals.

METHODS

To elucidate potential mechanisms regulating fetal nutrient availability, singleton sheep pregnancies were generated by embryo transfer. Pregnant ewes received either a 50% NRC (NR; n = 24) or 100% NRC (n = 7) diet from gestational Day 35 until necropsy on Day 125. Maternal weight did not correlate with fetal weight; therefore, the six heaviest (NR Non-IUGR) and five lightest (NR IUGR) fetuses from nutrient-restricted ewes, and seven 100% NRC fetuses, were compared to investigate differences in nutrient availability.

RESULTS

Insulin, multiple amino acids, and their metabolites, were reduced in fetal circulation of NR IUGR compared to NR Non-IUGR and 100% NRC pregnancies. In contrast, glucose in fetal fluids was not different between groups. There was a nearly two-fold reduction in placentome volume and fetal/maternal interface length in NR IUGR compared to NR Non-IUGR and 100% NRC pregnancies. Changes in amino acid concentrations were associated with altered expression of cationic (SLC7A2, SLC7A6, and SLC7A7) and large neutral (SLC38A2) amino acid transporters in placentomes.

DISCUSSION

Results establish a novel approach to study placental adaptation to maternal undernutrition in sheep and support the hypothesis that amino acids and polyamines are critical mediators of placental and fetal growth in sheep.

Cytokine profiles in maternal serum are candidates for predicting an optimal timing for the delivery in early-onset fetal growth restriction

OBJECTIVE

We examined whether maternal serum cytokine profiles of mothers with early-onset fetal growth restriction (FGR) were associated with delivery within 2 weeks after sampling during the third trimester.

STUDY DESIGN

This exploratory prospective cross-sectional study included a total of 20 singleton fetuses with early-onset FGR and 31 healthy controls. Maternal serum samples during the early third trimester were analyzed for 23 cytokines.

RESULTS

Of 20 fetuses with early-onset FGR, 14 had delivery within 2 weeks after sampling. Multivariate analysis revealed that maternal serum concentrations of soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) and soluble CD40 ligand (sCD40L) were independently associated with delivery within 2 weeks in early-onset FGR. Among cases of early-onset FGR, concentrations of almost all maternal serum cytokines were similar. Maternal serum sVEGFR-1 concentrations were high when delivery occurred within 2 weeks. Maternal serum sCD40L concentrations were elicited only in cases in which delivery within 2 weeks occurred due to fetal deterioration.

CONCLUSION

We identified two biomarkers, one specific for FGR and the other dependent on severity, that were significant components of angiogenic activities and inflammation factors. Imbalances in serum protein expression may have a substantial effect on the pathogenesis of FGR.

Prenatal dexamethasone exposure exerts sex-specific effect on placental oxygen and nutrient transport ascribed to the differential expression of IGF2

Background

Clinical studies have showed that dexamethasone exposure during pregnancy could cause fetal growth retardation, but the mechanism by which prenatal dexamethasone exposure influences placental nutrient transport is still unclear. This study investigated the impacts of prenatal dexamethasone on the placental oxygen and nutrient transport.

Methods

Pregnant Wistar rats were subcutaneously administered with dexamethasone from day 9 to day 20 of gestation at 0.2 or 0.8 mg/kg·d. Pregnant rats were sacrificed on gestational day 20. The placental tissue was collected for analysis.

Results

Prenatal dexamethasone exposure (PDE) declined the fetal weight and increased the intrauterine growth retardation (IUGR) rate in a dose-dependent manner. The total placental volume and the length, density and surface area of fetal capillaries in the labyrinth zone reduced in a dose-dependent manner. In addition, the thickness of syncytial membrane dose-dependently increased, resulting in a dose-dependent decrease in oxygen diffusion capacity. Furthermore, after PDE, the nutrient transport area and oxygen diffusion capacity of male placenta were lower than that of female placenta. The mRNA and protein expression of placental nutrient transporters including glucose transporter 1 (GLUT1), glucose transporter 3 (GLUT3), L-type amino acid transporter 1 (LAT1), lipoprotein lipase (LPL) and scavenger receptor class B type 1 (SRB1) increased in female placenta. However, in male placenta, the expression of LAT1, LPL and SRB1 was significantly decreased and GLUT1 and GLUT3 have a decrease trend. We further investigated the expression of insulin-like growth factor 1 (IGF1) and insulin-like growth factor 2 (IGF2) related to placental and fetal growth and development. Our study showed that the expression of IGF1 was significantly decreased both in male and female placentas after PDE. But the expression of IGF2 was significantly increased in female placentas while significantly decreased in male placentas.

Conclusions

Our study shows prenatal dexamethasone exposure exerts sex-specific influence on the placental oxygen and nutrient transport. This might be ascribed to the differential expression of IGF2 after PDE. These findings provide evidence on the dexamethasone-induced toxicity to the placenta and fetal development.

Metabolomic identification of placental alterations in fetal growth restriction

Introduction: Fetal growth restriction (FGR), viz., birth weight <10th percentile is a common pregnancy complication which increases the risk of adverse fetal and newborn outcomes. The placenta is the key organ for fetal growth as it controls oxygen and nutrient availability. This study aims to elucidate the mechanisms of and identify putative placental biomarkers for FGR using high-resolution metabolomics.Methods: Placenta samples from 19 FGR cases and 30 controls were analyzed using proton magnetic resonance (¹H NMR) spectroscopy and direct flow injection mass spectrometry with reverse-phase liquid-chromatography mass spectrometry (DI-LC-MS/MS). Significant concentration differences (p-value <.05) in 179 of the 220 metabolites were measured.Results: Of the 179 metabolites, 176 (98.3%) had reduced placental levels in FGR cases. The best performing metabolite model: 3-hydroxybutyrate, glycine and PCaaC42:0 achieved an AUC (95% CI) = 0.912 (0.814-1.000) with a sensitivity of 86.7% and specificity of 84.2% for FGR detection. Metabolite set enrichment analysis (MSEA) revealed significant (p < .05) perturbation of multiple placental metabolite pathways including urea metabolism, ammonia recycling, porphyrin metabolism, bile acid biosynthesis, galactose metabolism and perturbed protein biosynthesis.Conclusion: The placental metabolic pathway analysis revealed abnormalities that are consistent with fetal hepatic dysfunction in FGR. Near global reduction of metabolite concentrations was found in the placenta from FGR cases and metabolites demonstrated excellent diagnostic accuracy for FGR detection.

Complex, coordinated and highly regulated changes in placental signaling and nutrient transport capacity in IUGR

The most common cause of intrauterine growth restriction (IUGR) in the developed world is placental insufficiency, a concept often used synonymously with reduced utero-placental and umbilical blood flows. However, placental insufficiency and IUGR are associated with complex, coordinated and highly regulated changes in placental signaling and nutrient transport including inhibition of insulin and mTOR signaling and down-regulation of specific amino acid transporters, Na+/K+-ATPase, the Na+/H+-exchanger, folate and lactate transporters. In contrast, placental glucose transport capacity is unaltered and Ca2+-ATPase activity and the expression of proteins involved in placental lipid transport are increased in IUGR. These findings are not entirely consistent with the traditional view that the placenta is dysfunctional in IUGR, but rather suggest that the placenta adapts to reduce fetal growth in response to an inability of the mother to allocate resources to the fetus. This new model has implications for the understanding of the mechanisms underpinning IUGR and for the development of intervention strategies.

Cadmium exposure during pregnancy and lactation: materno-fetal and newborn repercussions of Cd(ii), and Cd-metallothionein complexes

Cadmium (Cd) is a non-physiological heavy metal that can be harmful at low concentrations. Increasing anthropogenic activities are incrementing the risk of accumulation of this heavy metal in different organs and tissues of the body. In the case of pregnant women, the threat is more serious due to the implications affecting not only their own health but also fetal development as well. Metallothioneins (MTs), small cysteine-rich proteins, are involved in zinc (Zn) and copper homeostasis in mammals but can, however, also bind with Cd if present. The accumulation of Cd in maternal tissues (e.g. placenta, maternal blood, and mammary glands) induces the synthesis of MTs, preferably MT2, in an attempt to sequester the metal to avoid toxicity. The formed Cd-MT complexes will avoid the Cd transport from the placenta to the fetus and end up accumulating in the maternal kidneys. At the same time, high concentrations of MTs will increase the formation of Zn-MT complexes, therefore decreasing the amount of Zn ions available to be transported to the fetus by means of Zn transporters such as ZnT2, ZIP14 and DMT1. Although MTs cannot transport Cd from the mother to the fetus, the divalent DMT1 transporter is suggested to carry the metal to the fetus. As a consequence, the low levels of Zn(ii) in the fetus, together with the presence of Cd(ii) coming from the mother either via the placenta and cord blood or via breast milk induce changes in the fetal development including fetal growth retardation, and low weight or height of the newborn. Likewise, the concentrations of Cd(ii) in the newborn can cause alterations such as cognitive disabilities. In summary, the presence of Cd(ii) in the maternal tissues will induce MT synthesis in an attempt to detoxify these tissues and reduce the possible toxicity of Cd in fetal and newborn tissues.

Surface-Functionalized Nanoparticles as Efficient Tools in Targeted Therapy of Pregnancy Complications

Minimizing exposure of the fetus to medication and reducing adverse off-target effects in the mother are the primary challenges in developing novel drugs to treat pregnancy complications. Nanomedicine has introduced opportunities for the development of novel platforms enabling targeted delivery of drugs in pregnancy. This review sets out to discuss the advances and potential of surface-functionalized nanoparticles in the targeted therapy of pregnancy complications. We first describe the human placental anatomy, which is fundamental for developing placenta-targeted therapy, and then we review current knowledge of nanoparticle transplacental transport mechanisms. Meanwhile, recent surface-functionalized nanoparticles for targeting the uterus and placenta are examined. Indeed, surface-functionalized nanoparticles could help prevent transplacental passage and promote placental-specific drug delivery, thereby enhancing efficacy and improving safety. We have achieved promising results in targeting the placenta via placental chondroitin sulfate A (plCSA), which is exclusively expressed in the placenta, using plCSA binding peptide (plCSA-BP)-decorated nanoparticles. Others have also focused on using placenta- and uterus-enriched molecules as targets to deliver therapeutics via surface-functionalized nanoparticles. Additionally, we propose that placenta-specific exosomes and surface-modified exosomes might be potential tools in the targeted therapy of pregnancy complications. Altogether, surface-functionalized nanoparticles have great potential value as clinical tools in the targeted therapy of pregnancy complications.

Placental histopathology in preterm fetal growth restriction

AIMS

Approximately 6-9% pregnancies are affected by fetal growth restriction (FGR). Placental alterations related to utero-placental insufficiency in FGR may induce placental vascular remodelling to the detriment of the fetus. The objective of this article was to study histopathological features of placentae in a cohort of preterm growth-restricted infants in comparison to a cohort of preterm appropriately grown infants.

METHODS

In a cohort of 40 preterm infants of 28-32 weeks' gestation, placental histopathology was evaluated by a histopathologist, who was blinded to the identity of the grouping. Twenty infants had FGR, while 20 were appropriate for gestational age (AGA). Predefined histopathological characteristics were assessed based on the Amsterdam Placental Workshop Group Consensus Statement.

RESULTS

The gestational age and birthweight of the FGR and AGA cohorts were 29.8 ± 1.3 versus 30 ± 0.9 weeks, P = 0.78 and 923 ± 168 versus 1403 ± 237 g, <0.001, respectively. Maternal vascular malperfusion, accelerated villous maturation and fetal vascular malperfusion were features that were significantly more common in FGR placentae.

CONCLUSION

Based on the results of the present study, specific placental histopathological changes may be present in FGR placentae, which may reflect the effects of utero-placental insufficiency.

Vascular changes in fetal growth restriction: clinical relevance and future therapeutics

Fetal growth restriction (FGR) affects about 5-10% pregnancies and is associated with poorer outcomes in the perinatal period. Additionally, long standing epidemiological data support its association with chronic diseases such as hypertension and diabetes. Cardiac and vascular adaptations in response to chronic hypoxemia due to utero-placental insufficiency are hallmarks of fetal adaptations. Investigators have attempted to identify these changes in the placenta at the microscopic and molecular level. The ex vivo dual perfusion model of the placenta enables the study of placental haemodynamics in growth-restricted pregnancies. Persistent arterial abnormalities (thickness and stiffness) noted on vascular ultrasound during fetal life through to the young-adult age group for those affected by FGR, seem to be a plausible link between in utero events and chronic circulatory diseases. Using these, this review reflects current thought on vascular maladaptive changes in the FGR cohorts and the role in investigating current and future therapeutics.

NLRP7 is increased in human idiopathic fetal growth restriction and plays a critical role in trophoblast differentiation

Fetal growth restriction (FGR) the leading cause of perinatal mortality and morbidity is highly related to abnormal placental development, and placentas from FGR pregnancies are often characterized by increased inflammation. However, the mechanisms of FGR-associated inflammation are far from being understood. NLRP7, a member of a family of receptors involved in the innate immune responses, has been shown to be associated with gestational trophoblastic diseases. Here, we characterized the expression and the functional role of NLRP7 in the placenta and investigated its involvement in the pathogenesis of FGR. We used primary trophoblasts and placental explants that were collected during early pregnancy, and established trophoblast-derived cell lines, human placental villi, and serum samples from early pregnancy (n = 38) and from FGR (n = 40) and age-matched controls (n = 32). Our results show that NLRP7 (i) is predominantly expressed in the trophoblasts during the hypoxic period of placental development and its expression is upregulated by hypoxia and (ii) increases trophoblast proliferation ([³H]-thymidine) and controls the precocious differentiation of trophoblasts towards syncytium (syncytin 1 and 2 and β-hCG production and xCELLigence analysis) and towards invasive extravillous trophoblast (2D and 3D cultures). We have also demonstrated that NLRP7 inflammasome activation in trophoblast cells increases IL-1β, but not IL-18 secretion. In relation to the FGR, we demonstrated that major components of NLRP7 inflammasome machinery are increased and that IL-1β but not IL-18 circulating levels are increased in FGR. Altogether, our results identified NLRP7 as a critical placental factor and provided evidence for its deregulation in FGR. NLRP7 inflammasome is abundantly expressed by trophoblast cells. It is regulated by a key parameter of placental development, hypoxia. It controls trophoblast proliferation, migration, and invasion and exhibits anti-apoptotic role. NLRP7 machinery is deregulated in FGR pregnancies. KEY MESSAGES: NLRP7 inflammasome is abundantly expressed by trophoblast cells. It is regulated by a key parameter of placental development, hypoxia. It controls trophoblast proliferation, migration, and invasion and exhibits anti-apoptotic role. NLRP7 machinery is deregulated in FGR pregnancies.

Placental ESRRG-CYP19A1 Expressions and Circulating 17-Beta Estradiol in IUGR Pregnancies

Introduction: Sex steroids are regulating factors for intrauterine growth. 17-β Estradiol (E2) is particularly critical to a physiological pregnancy, as increased maternal E2 was correlated to lower fetal weight at delivery. The placenta itself is a primary source of estrogens, synthetized from cholesterol precursors. Cytochrome P450 aromatase (encoded by CYP19A1 gene) is a rate-limiting enzyme for E2 biosynthesis. CYP19A1 transcription is supported by Estrogen Related-Receptor Gamma (ERRγ- ESRRG gene), which thus has an indirect role in placental steroidogenesis. Here we investigated maternal E2 levels and placental CYP19A1 and ESRRG expressions in pregnancies with IntraUterine Growth Restriction (IUGR). Methods: Singleton pregnancies were studied. E2 was measured in maternal plasma by electrochemiluminescence in 16 term controls and 11 IUGR (classified by umbilical artery doppler pulsatility index) at elective cesarean section, and also in 13 controls during pregnancy at a gestational age comparable to IUGR. CYP19A1 and ESRRG expressions were analyzed in placental tissue. Maternal/fetal characteristics, placental and molecular data were compared among study groups and tested for correlations. Results: Maternal E2 plasma concentrations were significantly decreased in IUGR compared to controls at delivery. When analyzing normal pregnancies at a gestational age similar to IUGR, E2 levels were not different to pathological cases. However, E2 levels at delivery positively correlated with placental efficiency. Placental CYP19A1 levels were significantly higher in IUGR placental tissue vs. controls, and specifically increased in female IUGR placentas. ESRRG expression was not different among groups. Discussion: We report a positive correlation between 17-β Estradiol levels and placental efficiency, that might indicate a disrupted steroidogenesis in IUGR pregnancies. Moreover, we show alterations of CYP19A1 expression in IUGR placentas, possibly indicating a compensatory effect to the adverse IUGR intrauterine environment, also depending on fetal sex. Further studies are needed to deeper investigate IUGR alterations in the complex interaction among molecules involved in placental steroidogenesis.

PLIN2 Is Essential for Trophoblastic Lipid Droplet Accumulation and Cell Survival During Hypoxia

Trophoblast hypoxia and injury, key components of placental dysfunction, are associated with fetal growth restriction and other complications of pregnancy. Accumulation of lipid droplets has been found in hypoxic nonplacental cells. Unique to pregnancy, lipid accumulation in the placenta might perturb lipid transport to the fetus. We tested the hypothesis that hypoxia leads to accumulation of lipid droplets in human trophoblasts and that trophoblastic PLIN proteins play a key role in this process. We found that hypoxia promotes the accumulation of lipid droplets in primary human trophoblasts. A similar accretion of lipid droplets was found in placental villi in vivo from pregnancies complicated by fetal growth restriction. In both situations, these changes were associated with an increased level of cellular triglycerides. Exposure of trophoblasts to hypoxia led to reduced fatty acid efflux and oxidation with no change in fatty acid uptake or synthesis. We further found that hypoxia markedly stimulated PLIN2 mRNA synthesis and protein expression, which colocalized to lipid droplets. Knockdown of PLIN2, but not PLIN3, enhanced trophoblast apoptotic death, and overexpression of PLIN2 promoted cell viability. Collectively, our data indicate that hypoxia enhances trophoblastic lipid retention in the form of lipid droplets and that PLIN2 plays a key role in this process and in trophoblast defense against apoptotic death. These findings also imply that this protective mechanism may lead to diminished trafficking of lipids to the developing fetus.

The human placental proteome secreted into the maternal and fetal circulations in normal pregnancy based on 4-vessel sampling

We sought to identify proteins secreted by the human placenta into the maternal and fetal circulations. Blood samples from the maternal radial artery and uterine vein and umbilical artery and vein were obtained during cesarean section in 35 healthy women with term pregnancy. Slow off-rate modified aptamer (SOMA) protein-binding technology was used to quantify 1310 known proteins. The uteroplacental and umbilical venoarterial concentration differences were calculated. Thirty-four proteins were significantly secreted by the placenta into the maternal circulation, including placental growth factor, growth/differentiation factor 15, and matrix metalloproteinase 12. There were 341 proteins significantly secreted by the placenta into the fetal circulation. Only 7 proteins were secreted into both the fetal and maternal circulations, suggesting a distinct directionality in placental protein release. We examined changes across gestation in the proteins found to be significantly secreted by the placenta into the maternal circulation using serial blood samples from healthy women. Among the 34 proteins secreted into the maternal circulation, 8 changed significantly across gestation. The identified profiles of secreted placental proteins will allow us to identify novel minimally invasive biomarkers for human placental function across gestation and discover previously unknown proteins secreted by the human placenta that regulate maternal physiology and fetal development.-Michelsen, T. M., Henriksen, T., Reinhold, D., Powell, T. L., Jansson, T. The human placental proteome secreted into the maternal and fetal circulations in normal pregnancy based on 4-vessel sampling.

The Pro-angiogenesis Of Exosomes Derived From Umbilical Cord Blood Of Intrauterine Growth Restriction Pigs Was Repressed Associated With MiRNAs

Dysfunctional umbilical cord blood (UCB) is a key factor for the development of intrauterine growth restriction (IUGR) in utero. Poor degrees of angiogenesis were observed during IUGR development. Here, it was demonstrated that NV-EXO (normal piglet's Umbilical Veins derived exosomes) promoted angiogenesis within the subdued pro-angiogenesis context of IV-EXO (IUGR piglet's Umbilical Veins derived exosomes). Investigation of the miRNA transcriptome of umbilical cord vein and artery exosomes between IUGR and normal littermates showed significant differences between umbilical veins from normal (NV) and IUGR (IV) piglets. Similar patterns were observed in normal (NA) and IUGR (IA) umbilical arteries as well. Moreover, the miRNAs expession level was more stable in NV. Further analysis revealed that miRNAs related to angiogenesis exhibited aberrant expression in IUGR pigs. The miRNA expression patterns between IUGR and normal piglets showed great difference. Expression of miR-150 in the tissues and UCB exosomes of IUGR pigs was significantly decreased. Up-regulation of miR-150 was able to increase proliferation, migration and tube formation of Human umbilical vein endothelial cells (HUVECs), suggesting a pro-angiogenic role. Furthermore, the data demonstrated that UCB derived miRNAs participate in fetal epigenetic regulation during pregnancy, suggesting a novel possible explanation for abnormal embryologic vascular development and several congenital cardiovascular diseases.

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.

Pathophysiology of placental-derived fetal growth restriction

Placental-related fetal growth restriction arises primarily due to deficient remodeling of the uterine spiral arteries supplying the placenta during early pregnancy. The resultant malperfusion induces cell stress within the placental tissues, leading to selective suppression of protein synthesis and reduced cell proliferation. These effects are compounded in more severe cases by increased infarction and fibrin deposition. Consequently, there is a reduction in villous volume and surface area for maternal-fetal exchange. Extensive dysregulation of imprinted and nonimprinted gene expression occurs, affecting placental transport, endocrine, metabolic, and immune functions. Secondary changes involving dedifferentiation of smooth muscle cells surrounding the fetal arteries within placental stem villi correlate with absent or reversed end-diastolic umbilical artery blood flow, and with a reduction in birthweight. Many of the morphological changes, principally the intraplacental vascular lesions, can be imaged using ultrasound or magnetic resonance imaging scanning, enabling their development and progression to be followed in vivo. The changes are more severe in cases of growth restriction associated with preeclampsia compared to those with growth restriction alone, consistent with the greater degree of maternal vasculopathy reported in the former and more extensive macroscopic placental damage including infarcts, extensive fibrin deposition and microscopic villous developmental defects, atherosis of the spiral arteries, and noninfectious villitis. The higher level of stress may activate proinflammatory and apoptotic pathways within the syncytiotrophoblast, releasing factors that cause the maternal endothelial cell activation that distinguishes between the 2 conditions. Congenital anomalies of the umbilical cord and placental shape are the only placental-related conditions that are not associated with maldevelopment of the uteroplacental circulation, and their impact on fetal growth is limited.

The impact of IUGR on pancreatic islet development and β-cell function

Placental insufficiency is a primary cause of intrauterine growth restriction (IUGR). IUGR increases the risk of developing type 2 diabetes mellitus (T2DM) throughout life, which indicates that insults from placental insufficiency impair β-cell development during the perinatal period because β-cells have a central role in the regulation of glucose tolerance. The severely IUGR fetal pancreas is characterized by smaller islets, less β-cells, and lower insulin secretion. Because of the important associations among impaired islet growth, β-cell dysfunction, impaired fetal growth, and the propensity for T2DM, significant progress has been made in understanding the pathophysiology of IUGR and programing events in the fetal endocrine pancreas. Animal models of IUGR replicate many of the observations in severe cases of human IUGR and allow us to refine our understanding of the pathophysiology of developmental and functional defects in islet from IUGR fetuses. Almost all models demonstrate a phenotype of progressive loss of β-cell mass and impaired β-cell function. This review will first provide evidence of impaired human islet development and β-cell function associated with IUGR and the impact on glucose homeostasis including the development of glucose intolerance and diabetes in adulthood. We then discuss evidence for the mechanisms regulating β-cell mass and insulin secretion in the IUGR fetus, including the role of hypoxia, catecholamines, nutrients, growth factors, and pancreatic vascularity. We focus on recent evidence from experimental interventions in established models of IUGR to understand better the pathophysiological mechanisms linking placental insufficiency with impaired islet development and β-cell function.

Fatty acid profile of maternal and fetal erythrocytes and placental expression of fatty acid transport proteins in normal and intrauterine growth restriction pregnancies

Long-chain polyunsaturated fatty acids (LC-PUFA), mainly docosahexaenoic (DHA) and arachidonic acids (AA), are critical for adequate fetal growth and development. We investigated mRNA expression of proteins involved in hydrolysis, uptake and/or transport of fatty acids in placenta of fifteen full term normal pregnancies and eleven pregnancies complicated by intrauterine growth restriction (IUGR) with normal umbilical blood flows. The mRNA expression of LPL, FATPs (-1, -2 and -4) and FABPs (-1 and -3) was increased in IUGR placentas, however, tissue profile of LC-PUFA was not different between groups. Erythrocytes from both mothers and fetuses of the IUGR group showed lower concentrations of AA and DHA and inferior DHA/ALA ratio compared to normal pregnancies (P < 0.05). We hypothesize that reduced circulating levels of AA and DHA could up-regulate mRNA expression of placental fatty acids transporters, as a compensatory mechanism, however this failed to sustain normal LC-PUFA supply to the fetus in IUGR.

The placental imprinted DLK1-DIO3 domain: a new link to prenatal and postnatal growth in humans

BACKGROUND

The developmentally important DLK1-DIO3 imprinted domain on human chromosome 14 is regulated by 2 differentially methylated regions, the intergenic differentially methylated region and the MEG3 differentially methylated region.

OBJECTIVE

The aim was to determine the natural variation in DNA methylation at these differentially methylated regions in human placentas, and to determine its link to gene expression levels at the domain. The second goal was to explore whether the domain's methylation and gene expression correlate with prenatal and early postnatal growth of the conceptus.

STUDY DESIGN

Using pyrosequencing, we determined methylation levels at CpG dinucleotides across the 2 regulatory differentially methylated regions in placentas from 91 healthy mothers. At birth, placentas and infants were weighed (gestational age 39 ± 1 weeks; birthweight SD score 0.1 ± 0.8) and placental biopsies were collected. RNA expression was quantitated by real-time polymerase chain reaction. Infants' weights and lengths were followed up monthly during the first year.

RESULTS

Methylation levels at the 2 regulatory differentially methylated regions were linked and varied considerably between placentas. MEG3 promoter differentially methylated region methylation correlated negatively with weight increase (β = -0.406, P = .001, R² = 0.206) and length increase (β = -0.363, P = .002, R² = 0.230) during the first postnatal year. The methylation level of the intergenic differentially methylated region correlated with DIO3 expression (β = 0.313, P = .032, R² = 0.152). Furthermore, the expression of both DIO3 and RTL1 (both imprinted genes within the DLK1-DIO3 domain) was negatively associated with birthweight (β = -0.331, P = .002, R² = 0.165; and β = -0.307, P = .005, R² = 0.159, respectively). RTL1 expression, in addition, was negatively linked to birth length (β = -0.306, P = .007, R² = 0.162).

CONCLUSION

Our combined findings strongly suggest that placental DNA methylation at the DLK1-DIO3 domain's intergenic differentially methylated region and MEG3 promoter differentially methylated region relates to measures of early human growth, and may thus contribute to its control.