Placental regulation of fetal nutrient supply

Fetal growth restriction exhibits various mTOR signaling in different regions of mouse placentas with altered lipid metabolism

Fetal growth restriction (FGR) is a common complication of pregnancy and can have significant impact on obstetric and neonatal outcomes. Increasing evidence has shown that the inhibited mechanistic target of rapamycin (mTOR) signaling in placenta is associated with FGR. However, interpretation of existing research is limited due to inconsistent methodologies and varying understanding of the mechanism by which mTOR activity contributes to FGR. Hereby, we have demonstrated that different anatomic regions of human and mouse placentas exhibited different levels of mTOR activity in normal compared to FGR pregnancies. When using the rapamycin-induced FGR mouse model, we found that placentas of FGR pregnancies exhibited abnormal morphological changes and reduced mTOR activity in the decidual-junctional layer. Using transcriptomics and lipidomics, we revealed that lipid and energy metabolism was significantly disrupted in the placentas of FGR mice. Finally, we demonstrated that maternal physical exercise during gestation in our FGR mouse model was associated with increased fetal and placental weight as well as increased placental mTOR activity and lipid metabolism. Collectively, our data indicate that the inhibited placental mTOR signaling contributes to FGR with altered lipid metabolism in mouse placentas, and maternal exercise could be an effective method to reduce the occurrence of FGR or alleviate the adverse outcomes associated with FGR.

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

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

Exploring the Role of Mediterranean and Westernized Diets and Their Main Nutrients in the Modulation of Oxidative Stress in the Placenta: A Narrative Review

Oxidative stress is a major cellular event that occurs in the placenta, fulfilling critical physiological roles in non-pathological pregnancies. However, exacerbated oxidative stress is a pivotal feature of different obstetric complications, like pre-eclampsia, fetal growth restriction, and other diseases. Compelling evidence supports the relevant role of diet during pregnancy, with pleiotropic consequences for maternal well-being. The present review aims to examine the complex background between oxidative stress and placental development and function in physiological conditions, also intending to understand the relationship between different dietary patterns and the human placenta, particularly how this could influence oxidative stress processes. The effects of Westernized diets (WDs) and high-fat diets (HFDs) rich in ultra-processed foods and different additives are compared with healthy patterns such as a Mediterranean diet (MedDiet) abundant in omega 3 polyunsaturated fatty acids, monounsaturated fatty acids, polyphenols, dietary fiber, and vitamins. Although multiple studies have focused on the role of specific nutrients, mostly in animal models and in vitro, further observational and intervention studies focusing on the placental structure and function in women with different dietary patterns should be conducted to understand the precise influence of diet on this organ.

Medical and Psychological Aspects of Pregnancy in Women with Obesity and after Bariatric Surgery

Chronic diseases are potential risk factors for pregnancy duration and neonatal outcomes. This narrative review aimed to summarize the research results on the specifics of pregnancy in women with obesity and after bariatric surgery. PubMed and Google Scholar databases were searched. Systematic reviews, meta-analyses, clinical trials, and references to identified articles from the last ten years (2013-2023) were included. Ultimately, 107 literature items were qualified. It has been shown that women with obesity planning pregnancy should reduce their body weight because obesity is a risk factor for adverse obstetric and neonatal outcomes. Bariatric surgery effectively reduces excessive body weight and the health risks in women with obesity during pregnancy and their offspring. However, at least a year interval between surgery and conception is recommended. An interdisciplinary medical team should provide patient care during pregnancy with knowledge and skills related to people after bariatric surgery. Due to the increased risk of mental disorders, especially depression, it is necessary to constantly monitor the mental state of women and provide psychological support and education on a healthy lifestyle during pregnancy and the postpartum period.

Hormonal Determinants of Growth and Weight Gain in the Human Fetus and Preterm Infant

The factors controlling linear growth and weight gain in the human fetus and newborn infant are poorly understood. We review here the changes in linear growth, weight gain, lean body mass, and fat mass during mid- and late gestation and the early postnatal period in the context of changes in the secretion and action of maternal, placental, fetal, and neonatal hormones, growth factors, and adipocytokines. We assess the effects of hormonal determinants on placental nutrient delivery and the impact of preterm delivery on hormone expression and postnatal growth and metabolic function. We then discuss the effects of various maternal disorders and nutritional and pharmacologic interventions on fetal and perinatal hormone and growth factor production, growth, and fat deposition and consider important unresolved questions in the field.

Insights into Transcriptomic Differences in Ovaries between Lambs and Adult Sheep after Superovulation Treatment

Superovulation technology shows a great potential for shortening breeding time. Using the juvenile superovulation technology, juvenile animals can generate more follicles than adult animals. By sequencing using high-throughput methods, we studied and described differentially expressed (DE) long non-coding RNA (lncRNAs) and messenger RNAs (mRNAs) in the ovaries of young and adult sheep. Herein, 242 DE lncRNAs and 3150 DE mRNAs were screened. Through GO and KEGG analyses, we obtained genes related to ovarian/follicle development and ovulation in DE mRNAs, including OaFSHR, OaLHCGR, OaLDLR, OaZP3, OaSCARB1, and OaPDGFRA; through lncRNA-mRNA correlation analysis, we found that genes associated with ovarian/follicle development or ovulation include: XR_003585520.1, MSTRG.15652.1, XR_003588840.1, and their paired genes PDGFC, LRP5, and LRP1. We observed a synergistic effect between PDGFR and LRP1. PDGFR may play a leading role compared with LRP1. The induced LHCGR in lambs is higher than in adult sheep, showing more sensitivity to LH. The release of the oocytes was stimulated. Among the three lncRNAs, we found that XR_003588840.1 was significantly different and might perform a regulatory role in ovarian/follicle growth or ovulation.

Obesity Affects Maternal and Neonatal HDL Metabolism and Function

Pregravid obesity is one of the major risk factors for pregnancy complications such as gestational diabetes mellitus (GDM) and an increased risk of cardiovascular events in children of affected mothers. However, the biological mechanisms that underpin these adverse outcomes are not well understood. High-density lipoproteins (HDLs) are antiatherogenic by promoting the efflux of cholesterol from macrophages and by suppression of inflammation. Functional impairment of HDLs in obese and GDM-complicated pregnancies may have long-term effects on maternal and offspring health. In the present study, we assessed metrics of HDL function in sera of pregnant women with overweight/obesity of the DALI lifestyle trial (prepregnancy BMI ≥ 29 kg/m2) and women with normal weight (prepregnancy BMI < 25 kg/m2), as well as HDL functionalities in cord blood at delivery. We observed that pregravid obesity was associated with impaired serum antioxidative capacity and lecithin−cholesterol acyltransferase activity in both mothers and offspring, whereas maternal HDL cholesterol efflux capacity was increased. Interestingly, functionalities of maternal and fetal HDL correlated robustly. GDM did not significantly further alter the parameters of HDL function and metabolism in women with obesity, so obesity itself appears to have a major impact on HDL functionality in mothers and their offspring.

Unfolding the role of placental-derived Extracellular Vesicles in Pregnancy: From homeostasis to pathophysiology

The human placenta is a critical structure with multiple roles in pregnancy, including fetal nutrition and support, immunological, mechanical and chemical barrier as well as an endocrine activity. Besides, a growing body of evidence highlight the relevance of this organ on the maternofetal wellbeing not only during gestation, but also from birth onwards. Extracellular vesicles (EVs) are complex macromolecular structures of different size and content, acting as carriers of a diverse set of molecules and information from donor to recipient cells. Since its early development, the production and function of placental-derived EVs are essential to ensure an adequate progress of pregnancy. In turn, the fetus receives and produce their own EVs, highlighting the importance of these components in the maternofetal communication. Moreover, several studies have shown the clinical relevance of EVs in different obstetric pathologies such as preeclampsia, infectious diseases or gestational diabetes, among others, suggesting that they could be used as pathophysiological biomarkers of these diseases. Overall, the aim of this article is to present an updated review of the published basic and translational knowledge focusing on the role of placental-derived EVs in normal and pathological pregnancies. We suggest as well future lines of research to take in this novel and promising field.

Maternal Amino Acid Mixtures Supplementation during Late Gestation and Lactation Improved Growth Performance of Piglets through Improving Colostrum Composition and Antioxidant Capacity

During late gestation and lactation, oxidative stress in sows can affect their health and reproductive performance. Supplemental amino acid contributes to the antioxidant capacity of pigs. This study was conducted to evaluate the effects of different combinations of Gln, Leu and γ-GABA (amino acid mixtures, AAMs) during late gestation and lactation on the performance of the sows and their offspring. Fifty large white × landrace sows were randomly assigned to 5 groups (n = 10), including a control group and four AAMs groups (AAMs1, Gln + Leu; AAMs2 (Gln + GABA; AAMs3, Leu + GABA; AAMs4, Gln + Leu + GABA). AAMs supplementation improved the antioxidant capacity of sows, including significantly enhanced total antioxidant capacity in AAMs2, 3 and 4 groups and reduced malonaldehyde concentration in AAMs1, 3 and 4 groups. Additionally, all AAMs significantly increased lactoprotein, total solid and IgA levels of colostrum in sows during lactation. Average body weight of piglets on day 21 after birth in all AAMs groups were significantly increased. Furthermore, the significantly increased total antioxidant capacity was observed in the piglets of every AAMs group. In conclusion, supplementing AAMs during late gestation and lactation improved the antioxidant capacity of sows and colostrum composition, thereby enhancing antioxidant status and the growth performance of piglets. This study provides the possibility of maternal amino acid mixtures to improve the productivity of the swine industry.

Prenatal exposure to parabens in association with cord serum adipokine levels and offspring size at birth

BACKGROUND

Paraben exposure is linked to the release of adipokine such as leptin and adiponectin, and both paraben and adipokine may affect fetal growth. The present study aimed to explore the associations among maternal paraben exposure, adipokine level and offspring size.

METHODS

942 mother-newborn pairs from the Sheyang Mini Birth Cohort Study (SMBCS) were enrolled. Data of birth weight, length, head circumference and ponderal index (PI) were obtained from medical records. Maternal urinary parabens were determined by gas chromatography tandem mass spectrometry. Cord serum leptin and adiponectin were measured using ELISA assay. Generalized linear regression was applied to explore the associations among parabens, adipokines and offspring size.

RESULTS

The median levels of leptin and adiponectin were 13.13 μg/L and 161.82 μg/mL. Benzylparaben level was positively associated with leptin (regression coefficient (β) = 0.06, 95% confidence interval (CI): 0.03-0.09; p < 0.01). Leptin level was positively associated with neonatal weight (β = 84.11, 95% CI: 63.22-105.01; p < 0.01), length (β = 0.25, 95% CI: 0.14-0.37; p < 0.01), head circumference (β = 0.15, 95% CI: 0.07-0.22; p < 0.01) and PI (β = 0.23, 95% CI: 0.08-0.39; p < 0.01). Adiponectin was positively associated with neonatal weight (β = 75.94, 95% CI: 29.65-122.23; p < 0.01) and PI (β = 0.43, 95% CI: 0.09-0.77; p = 0.01). Urinary propylparaben concentration (β = -0.10, 95% CI: -0.17 to -0.02; p = 0.01) was negatively associated with head circumference. Sex-stratified analyses indicated the negative association of propylparaben and head circumference was only remained in male neonates.

CONCLUSIONS

Prenatal paraben exposure might affect cord serum leptin levels. Both paraben and adipokine levels may affect fetal growth, and sex-specific differences may exist.

Resistin Modulates Low-Density Lipoprotein Cholesterol Uptake in Human Placental Explants via PCSK9

Maternal metabolic status influences pregnancy and, consequently, the perinatal outcome. Resistin is a pro-inflammatory adipokine predominantly expressed and secreted by mononuclear cells, adipose tissue, and placental trophoblastic cells during pregnancy. Recently, we reported an inverse association between maternal resistin levels and fetal low-density lipoprotein cholesterol (LDL-C). Then, in this work, we used a human placental explant model and the trophoblast cell line JEG-3 to evaluate whether resistin affects placental LDL-C uptake. Resistin exposure induced the transcription factor SREBP-2, LDLR, and PCSK9 mRNA expression, and changes at the protein level were confirmed by immunohistochemistry and Western blot. However, for LDLR, the changes were not consistent between mRNA and protein levels. Using a labeled LDL-cholesterol (BODIPY FL LDL), uptake assay demonstrated that the LDL-C was significantly decreased in placental explants exposed to a high dose of resistin and a lesser extent in JEG-3 cells. In summary, resistin induces PCSK9 expression in placental explants and JEG-3 cells, which could be related to negative regulation of the LDLR by lysosomal degradation. These findings suggest that resistin may significantly regulate the LDL-C uptake and transport from the maternal circulation to the fetus, affecting its growth and lipid profile.

The Pivotal Role of the Placenta in Normal and Pathological Pregnancies: A Focus on Preeclampsia, Fetal Growth Restriction, and Maternal Chronic Venous Disease

The placenta is a central structure in pregnancy and has pleiotropic functions. This organ grows incredibly rapidly during this period, acting as a mastermind behind different fetal and maternal processes. The relevance of the placenta extends far beyond the pregnancy, being crucial for fetal programming before birth. Having integrative knowledge of this maternofetal structure helps significantly in understanding the development of pregnancy either in a proper or pathophysiological context. Thus, the aim of this review is to summarize the main features of the placenta, with a special focus on its early development, cytoarchitecture, immunology, and functions in non-pathological conditions. In contraposition, the role of the placenta is examined in preeclampsia, a worrisome hypertensive disorder of pregnancy, in order to describe the pathophysiological implications of the placenta in this disease. Likewise, dysfunction of the placenta in fetal growth restriction, a major consequence of preeclampsia, is also discussed, emphasizing the potential clinical strategies derived. Finally, the emerging role of the placenta in maternal chronic venous disease either as a causative agent or as a consequence of the disease is equally treated.

Leucine supplementation during late gestation globally alters placental metabolism and nutrient transport via modulation of the PI3K/AKT/mTOR signaling pathway in sows

In a previously published study we reported that sow dietary leucine supplementation during late pregnancy significantly improved newborn piglet birth weight by stimulating protein synthesis in the longissimus dorsi muscle. However, there is still limited knowledge as to whether leucine can exert its effects on the placenta, one of the most important temporal organs during pregnancy, to promote maternal-fetal nutrient supply and thus contribute to fetal intrauterine development. Therefore, we tested this hypothesis in the present study. In total, 150 sows at day 90 of gestation were divided into three groups and fed with either a control diet (CON), CON + 0.4% Leu or CON + 0.8% Leu, respectively, until parturition. Placental metabolomics, full spectrum amino acids and nutrient transporters were systematically analyzed after sample collection. The results indicated that Leu supplementation led to an altered placental metabolism with an increased number of metabolites related to glycolysis and the oxidation of fatty acids, as well as elevated levels of amino acid accumulation in the placenta. In addition, nutrient transporters of amino acids, glucose and fatty acids in the placenta were globally up-regulated and several enzymes related to energy metabolism, including hexokinase, succinate dehydrogenase, lactated hydrogenase, glycogen phosphorylase and hydroxyacyl-CoA-dehydrogenase, were also significantly increased with no change observed in the antioxidative status of those groups with Leu supplementation. Furthermore, the phosphorylation of PI3K, Akt, and mTOR was enhanced in the placenta of sows undergoing Leu treatment. Collectively, we concluded that supplementing the diets of sows with Leu during late gestation globally altered placental metabolism and promoted maternal-fetus nutrient transport (amino acids, glucose, and fatty acids) via modulation of the PI3K/Akt/mTOR signaling pathway.

Lipid signatures reflect the function of the murine primary placentation

The placenta regulates maternal-fetal communication, and its defect leads to significant pregnancy complications. The maternal and embryonic circulations are primitively connected in early placentation, but the function of the placenta during this developmentally essential period is relatively unknown. We thus performed a comparative proteomic analysis of the placenta before and after primary placentation and found that the metabolism and transport of lipids were characteristically activated in this period. The placental fatty acid (FA) carriers in specific placental compartments were upregulated according to gestational age, and metabolomic analysis also showed that the placental transport of FAs increased in a time-dependent manner. Further analysis of two mutant mice models with embryonic lethality revealed that lipid-related signatures could reflect the functional state of the placenta. Our findings highlight the importance of the nutrient transport function of the primary placenta in the early gestational period and the role of lipids in embryonic development.

FPR2 serves a role in recurrent spontaneous abortion by regulating trophoblast function via the PI3K/AKT signaling pathway

Recurrent spontaneous abortion (RSA) effects both the physical and mental health of women of reproductive age. Trophoblast dysfunction may result in RSA due to shallow placental implantation. The mechanisms underlying formyl peptide receptor 2 (FPR2) on the biological functions of trophoblasts remain to be elucidated. The present study aimed to explore the potential functions of FPR2, a G protein‑coupled receptor, in placental trophoblasts. The location and expression levels of FPR2 in the villi tissue of patients with RSA were detected using immunohistochemical staining, reverse transcription‑quantitative PCR and western blotting. Following the transfection of small interfering RNA targeting FPR2 in HTR‑8/SVneo cells, a Cell Counting Kit‑8 assay was used to determine the levels of cell viability. Flow cytometry was used to examine the levels of cell apoptosis and gap closure and Transwell assays were carried out to evaluate the levels of cell migration and invasion. A tube formation assay was performed to detect the levels of capillary‑like structure formation. Western blotting was used to detect the expression levels of proteins in the associated signaling pathways. The expression of FPR2 was present in villi trophoblasts and was markedly increased in patients with RSA. The levels of trophoblast invasion, migration and tube formation were markedly increased following FPR2 knockdown, whereas the levels of apoptosis were markedly decreased. In addition, FPR2 knockdown caused an increase in the phosphorylation levels of AKT and PI3K. Thus, FPR2 may be involved in the regulation of trophoblast function via the PI3K/AKT signaling pathway. The results of the present study provided a theoretical basis for the use of FPR2 as a target for the treatment of trophoblast‑associated diseases, such as RSA.

Maternal yeast-based nucleotide supplementation decreased stillbirth by regulating nutrient metabolism

BACKGROUND

As an enzymatic product of yeast, yeast-based nucleotide (YN) is rich in nucleotides. To test the effects of maternal dietary supplementation with YN during late pregnancy on placental nutrient transport and nutrient metabolism in neonatal piglets, 64 pregnant sows (day 85 ± 3) were assigned into two groups: (i) control (CON) and (ii) treatment (YN; 4 g kg^-1 ). Blood, placenta and liver samples of neonates during delivery were collected.

RESULTS

The results showed that maternal YN supplementation decreased stillbirth rate and intra-uterine growth restriction rate (P < 0.05). In addition, maternal YN supplementation increased total serum protein, albumin and total cholesterol (P < 0.05). Furthermore, in neonatal piglets in the YN group, both serum amino acidand nucleotide profiles were affected, as well as liver amino acid, and fatty acid profiles were regulated (P < 0.05). Moreover, maternal YN supplementation increased liver mRNA expression of SLC28A3, SLC29A1, SLC29A2, PC, PCK1, FBP1, SREBP1c, HSL and CYP7a1 of neonatal piglets (P < 0.05). Meanwhile, there was a decrease in placental gene expression of EAAT2, EAAT3, LAT1 and PAT1, as well as lower protein expression of peroxisome proliferator-activated receptor (PPAR)γ, AKT, phosphorylated-AKT, phosphorylated-mammalian target of rapamycin (mTOR) and Raptor, in the YN group (P < 0.05).

CONCLUSION

Taken together, these results indicate that maternal YN supplementation regulates placental nutrient transport by regulating the mTOR complex 1-PPAR pathway, and affects the liver metabolism of nucleotides, amino acids and fatty acids in neonatal piglets, thereby improving the reproductive performance of sow to a certain extent. © 2020 Society of Chemical Industry.

Role of Placental Glucose Transporters in Determining Fetal Growth

Maternal nutrient availability and its transport through the placenta are crucial for fetal development. Nutrients are transported to the fetus via specific transporters present on the microvillous (MVM) and basal membrane (BM) of the placenta. Glucose is the most abundant nutrient transferred to the fetus and plays a key role in the fetal growth and development. The transfer of glucose across the human placenta is directly proportional to maternal glucose concentrations, and is mediated by glucose transporter family proteins (GLUTs). Maternal glucose concentration influences expression and activity of GLUTs in the MVM (glucose uptake) and BM (glucose delivery). Alteration in the number and function of these transporters may affect the growth and body composition of the fetus. The thin-fat phenotype of the Indian baby (low ponderal index, high adiposity) is proposed as a harbinger of future metabolic risk. We propose that placental function mediated through nutrient transporters contributes to the phenotype of the baby, specifically that glucose transporters will influence neonatal fat. This review discusses the role of various glucose transporters in the placenta in determining fetal growth and body composition, in light of the above hypothesis.

Allergic Food Sensitization and Disease Manifestation in the Fetus and Infant: A Perspective

Even though allergic disease is identified in the first year of life, it is often in a less forward fashion, with elements of a wait and see approach. If the infant does not have an anaphylactic food reaction, other less dramatic allergic phenomenon is often under-emphasized, waiting for additional concerns. We approached this with a conception to first conduct birthday surveys, attempting to link intrauterine and peri-birth circumstances to affect better allergy recognition in young infants.

Role of Long Chain Fatty Acids in Developmental Programming in Ruminants

Simple Summary

The objective of the current review is to provide a broad perspective on developmental program aspects of dietary n-3 FA supplementation in ruminants during pre-conception, conception, pregnancy, early life, including its effects on production, lipid metabolism, and health of the offspring. Offspring growth and metabolism could change depending on the FA profile and the stage of gestation when the dam is supplemented. Despite this extended review we are highlighting areas that we consider that there is a lack of information.

Abstract

Nutrition plays a critical role in developmental programs. These effects can be during gametogenesis, gestation, or early life. Omega-3 polyunsaturated fatty acids (PUFA) are essential for normal physiological functioning and for the health of humans and all domestic species. Recent studies have demonstrated the importance of n-3 PUFA in ruminant diets during gestation and its effects on pre-and postnatal offspring growth and health indices. In addition, different types of fatty acids have different metabolic functions, which affects the developmental program differently depending on when they are supplemented. This review provides a broad perspective of the effect of fatty acid supplementation on the developmental program in ruminants, highlighting the areas of a developmental program that are better known and the areas that more research may be needed.

Towards an Optimized Fetal DHA Accretion: Differences on Maternal DHA Supplementation Using Phospholipids vs. Triglycerides during Pregnancy in Different Models

Docosahexaenoic acid (DHA) supplementation during pregnancy has been recommended by several health organizations due to its role in neural, visual, and cognitive development. There are several fat sources available on the market for the manufacture of these dietary supplements with DHA. These fat sources differ in the lipid structure in which DHA is esterified, mainly phospholipids (PL) and triglycerides (TG) molecules. The supplementation of DHA in the form of PL or TG during pregnancy can lead to controversial results depending on the animal model, physiological status and the fat sources utilized. The intestinal digestion, placental uptake, and fetal accretion of DHA may vary depending on the lipid source of DHA ingested by the mother. The form of DHA used in maternal supplementation that would provide an optimal DHA accretion for fetal brain development, based on the available data obtained most of them from different animal models, indicates no consistent differences in fetal accretion when DHA is provided as TG or PL. Other related lipid species are under evaluation, e.g., lyso-phospholipids, with promising results to improve DHA bioavailability although more studies are needed. In this review, the evidence on DHA bioavailability and accumulation in both maternal and fetal tissues after the administration of DHA supplementation during pregnancy in the form of PL or TG in different models is summarized.

mTORC1 Transcriptional Regulation of Ribosome Subunits, Protein Synthesis, and Molecular Transport in Primary Human Trophoblast Cells

Mechanistic Target of Rapamycin Complex 1 (mTORC1) serves as positive regulator of placental nutrient transport and mitochondrial respiration. The role of mTORC1 signaling in modulating other placental functions is largely unexplored. We used gene array following silencing of raptor to identify genes regulated by mTORC1 in primary human trophoblast (PHT) cells. Seven hundred and thirty-nine genes were differentially expressed; 487 genes were down-regulated and 252 up-regulated. Bioinformatic analyses demonstrated that inhibition of mTORC1 resulted in decreased expression of genes encoding ribosomal proteins in the 60S and 40S ribosome subunits. Furthermore, down-regulated genes were functionally enriched in genes involved in eIF2, sirtuin and mTOR signaling, mitochondrial function, and glutamine and zinc transport. Stress response genes were enriched among up-regulated genes following mTORC1 inhibition. The protein expression of ribosomal proteins RPL26 (RPL26) and Ribosomal Protein S10 (RPS10) was decreased and positively correlated to mTORC1 signaling and System A amino acid transport in human placentas collected from pregnancies complicated by intrauterine growth restriction (IUGR). In conclusion, mTORC1 signaling regulates the expression of trophoblast genes involved in ribosome and protein synthesis, mitochondrial function, lipid metabolism, nutrient transport, and angiogenesis, representing novel links between mTOR signaling and multiple placental functions critical for normal fetal growth and development.

Maternal Anthropometric Factors and Circulating Adipokines as Predictors of Birth Weight and Length

Pregnancy is a period of serial metabolic and hormonal changes in the woman's body. Factors such as circulating adipokines affect the fetal period and may cause long-term changes in metabolic pathways at the cellular, tissue, or organ level. The nutritional status of the pregnant woman affects the course of pregnancy, delivery, and confinement, as well as the health of the offspring following birth and in subsequent years. Adipokine hormones essential for modulating metabolism during pregnancy include adiponectin and leptin. This study aimed to assess maternal anthropometric parameters and plasma concentrations of specific adipokines as predictive measures of newborn birth weight, birth length, and ponderal index. Anthropometric measurements (prepregnancy body weight and height) were obtained from 168 surveyed Polish women. Data related to the birth parameters of 168 newborns (body length and mass) were derived from clinical records. Circulating maternal adiponectin and leptin levels at birth were determined. Significant correlations between newborn birth weight and maternal prepregnancy body mass index (p < 0.05) or maternal weight gain during pregnancy (p < 0.05) were observed. Women with below normal weight gain during pregnancy were more likely to give birth to newborns with significantly lower birth weight than women with excessive weight gain during pregnancy (p < 0.05). Maternal plasma concentrations of leptin were significantly related to prepregnancy maternal body mass index (p < 0.05), and concentrations of adiponectin and leptin were significantly related to weight gain during pregnancy (p < 0.05). However, they did not affect the birth parameters of the newborn.

Physical Activity During Pregnancy Is Associated with Increased Placental FATP4 Protein Expression

Placental function is of utmost importance to ensure proper fetal development in utero. Among the placenta's many roles includes the passage of sufficient macronutrients, such as glucose, amino acids, and fatty acids, to the fetus. Macronutrients are carried from maternal circulation to the fetus across transporters within the placenta. The objective of this study was to examine the impact of (i) an acute bout of exercise and (ii) chronic exercise participation on placenta nutrient transporter expression and localization. To investigate the effect of acute exercise, pre- and post-exercise serum was collected from pregnant (n = 5) and non-pregnant (n = 5) women who underwent a moderate-intensity exercise session and used to treat BeWo cells. To assess chronic physical activity, we analyzed term placenta from women categorized as active (n = 10) versus non-active (n = 10). Protein expression and localization for the transporters GLUT1, SNAT1, and FATP4 were examined for both groups. GLUT1 expression in BeWo cells treated with serum from pregnant women was higher compared with that from non-pregnant, independent of exercise. FATP4 protein expression was elevated in the term placenta of active women. Immunohistochemistry analysis of term placenta illustrated increased staining of FATP4 in placental tissue from active women and differential staining pattern of GLUT1 depending on physical activity status. Chronic exercise during pregnancy increases the expression of placental FATP4 in vivo, suggesting greater metabolism and usage of fatty acids. Additionally, serum from pregnant women could contain factors that increase GLUT1 protein expression in vitro. BeWo cells treated with pre- and post-exercise serum from pregnant women resulted in greater GLUT1 expression compared with those treated with pre- and post-exercise serum from non-pregnant women. Physical activity appears to differentially impact key placental transporters involved in the transfer and availability of nutrients from mother to fetus. Future research ought to examine the mechanisms involved in regulating these changes and their impact on fetal growth and health.

Maternal fats and pregnancy complications: Implications for long-term health

Pregnancy imposes increased nutritional requirements for the well being of the mother and fetus. Maternal lipid metabolism is critical for fetal development and long-term health of the offspring as it plays a key role in energy storage, tissue growth and cell signaling. Maternal fat composition is considered as a modifiable risk for abnormal lipid metabolism and glucose tolerance during pregnancy. Data derived from observational studies demonstrate that higher intake of saturated fats during pregnancy is associated with pregnancy complications (preeclampsia, gestational diabetes mellitus and preterm delivery) and poor birth outcomes (intra uterine growth retardation and large for gestational age babies). On the other hand, prenatal long chain polyunsaturated fatty acids status is shown to improve birth outome. In this article, we discuss the role of maternal lipids during pregnancy on fetal growth and development and its consequences on the health of the offspring.

The Effects of Selenium Supplementation on Gene Expression Related to Insulin and Lipid Metabolism, and Pregnancy Outcomes in Patients with Gestational Diabetes Mellitus: a Randomized, Double-Blind, Placebo-Controlled Trial

This study was performed to evaluate the effects of selenium supplementation on gene expression related to insulin and lipid metabolism, and pregnancy outcomes in patients with gestational diabetes mellitus (GDM). The current randomized, double-blind, placebo-controlled clinical trial was conducted in 36 patients with GDM. Participants were randomly divided into two groups to intake either 200 μg/day selenium supplements as selenium yeast or placebo (n = 18 each group) for 6 weeks. Selenium supplementation upregulated peroxisome proliferator-activated receptor gamma (P = 0.03) and glucose transporter 1 (GLUT-1) (P = 0.01) in lymphocytes of subjects with GDM compared with the placebo. Selenium supplementation did not affect gene expression of low-density lipoprotein receptor (LDLR) and lipoprotein(a) [Lp(a)]. Supplementation with selenium had a significant decrease in incidence of newborns' hyperbilirubinemia (5.6% vs. 33.3%, P = 0.03) and newborns' hospitalization (5.6% vs. 33.3%, P = 0.03) compared with the placebo. Overall, we found that selenium supplementation for 6 weeks among patients with GDM significantly increased PPAR-γ and GLUT-1 expression, but did not affect gene expression of LDLR and LP(a). It also reduced incidence of newborns' hyperbilirubinemia and newborns' hospitalization. Clinical trial registration number: http://www.irct.ir: IRCT20170513033941N35.

A population-based resource for intergenerational metabolomics analyses in pregnant women and their children: the Generation R Study

INTRODUCTION

Adverse exposures in early life may predispose children to cardio-metabolic disease in later life. Metabolomics may serve as a valuable tool to disentangle the metabolic adaptations and mechanisms that potentially underlie these associations.

OBJECTIVES

To describe the acquisition, processing and structure of the metabolomics data available in a population-based prospective cohort from early pregnancy onwards and to examine the relationships between metabolite profiles of pregnant women and their children at birth and in childhood.

METHODS

In a subset of 994 mothers-child pairs from a prospective population-based cohort study among pregnant women and their children from Rotterdam, the Netherlands, we used LC-MS/MS to determine concentrations of amino acids, non-esterified fatty acids, phospholipids and carnitines in blood serum collected in early pregnancy, at birth (cord blood), and at child's age 10 years.

RESULTS

Concentrations of diacyl-phosphatidylcholines, acyl-alkyl-phosphatidylcholines, alkyl-lysophosphatidylcholines and sphingomyelines were the highest in early pregnancy, concentrations of amino acids and non-esterified fatty acids were the highest at birth and concentrations of alkyl-lysophosphatidylcholines, free carnitine and acyl-carnitines were the highest at age 10 years. Correlations of individual metabolites between pregnant women and their children at birth and at the age of 10 years were low (range between r = - 0.10 and r = 0.35).

CONCLUSION

Our results suggest that unique metabolic profiles are present among pregnant women, newborns and school aged children, with limited intergenerational correlations between metabolite profiles. These data will form a valuable resource to address the early metabolic origins of cardio-metabolic disease.

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.

Should formula for infants provide arachidonic acid along with DHA? A position paper of the European Academy of Paediatrics and the Child Health Foundation

Recently adopted regulatory standards on infant and follow-on formula for the European Union stipulate that from February 2020 onwards, all such products marketed in the European Union must contain 20-50 mg omega-3 DHA (22:6n-3) per 100 kcal, which is equivalent to about 0.5-1% of fatty acids (FAs) and thus higher than typically found in human milk and current infant formula products, without the need to also include ω-6 arachidonic acid (AA; 20:4n-6). This novel concept of infant formula composition has given rise to concern and controversy because there is no accountable evidence on its suitability and safety in healthy infants. Therefore, international experts in the field of infant nutrition were invited to review the state of scientific research on DHA and AA, and to discuss the questions arising from the new European regulatory standards. Based on the available information, we recommend that infant and follow-on formula should provide both DHA and AA. The DHA should equal at least the mean content in human milk globally (0.3% of FAs) but preferably reach 0.5% of FAs. Although optimal AA intake amounts remain to be defined, we strongly recommend that AA should be provided along with DHA. At amounts of DHA in infant formula up to ∼0.64%, AA contents should at least equal the DHA contents. Further well-designed clinical studies should evaluate the optimal intakes of DHA and AA in infants at different ages based on relevant outcomes.

Delayed access to feed alters expression of genes associated with carbohydrate and amino acid utilization in newly hatched broiler chicks

Newly hatched chicks must transition from lipid-rich yolk to carbohydrate-rich feed as their primary nutrient source, and posthatch delays in access to feed can have long-term negative consequences on growth and metabolism. In this study, impacts of delayed access to feed at hatch on expression of genes related to nutrient uptake and utilization in two metabolically important tissues, liver and muscle, were determined in broiler (meat-type) chickens. Hatched chicks were given access to feed within 3 h (fed) or delayed access to feed for 48 h (delayed fed), and liver and breast muscle were collected from males at hatch and 4 h, 1 day, 2 days, 4 days, and 8 days posthatch for analysis of gene expression. Differential expression of carbohydrate response element-binding protein and peroxisome proliferator-activated receptor-γ in muscle and liver was observed, with results indicating a transitional delay from lipid to carbohydrate metabolism when hatched chicks were not given immediate access to feed. Extended upregulation of insulin receptor mRNA was observed in both tissues in delayed fed birds, suggesting increased sensitivity to circulating levels of the hormone. Developmental delays in expression patterns of cationic amino acid transporters 1 and 2 in both tissues and large neutral amino acid transporter 1 in muscle were also apparent when immediate feed access was prevented. These data suggest that delayed transition to carbohydrate use and altered nutrient transport and utilization within liver and breast muscle are key factors negatively affecting growth and metabolism following delayed feed access in broiler chickens.

The significant role of carnitine and fatty acids during pregnancy, lactation and perinatal period. Nutritional support in specific groups of pregnant women

BACKGROUND & AIMS

Pregnancy is characterized by a complexity of metabolic processes that may impact fetal health and development. Women's nutrition during pregnancy and lactation is considered important for both mother and infant. This review aims to investigate the significant role of fatty acids and carnitine during pregnancy and lactation in specific groups of pregnant and lactating women.

METHODS

The literature was reviewed using relevant data bases (e.g. Pubmed, Scopus, Science Direct) and relevant articles were selected to provide information and data for the text and associated Tables.

RESULTS

Dynamic features especially of plasma carnitine profile during pregnancy and lactation, indicate an extraordinarily active participation of carnitine in the intermediary metabolism both in pregnant woman and in neonate and may also have implications for health and disease later in life. Maternal diets rich in trans and saturated fatty acids can lead to impairments in the metabolism and development of the offspring, whereas the consumption of long chain-polyunsaturated fatty acids during pregnancy plays a beneficial physiologic and metabolic role in the health of offspring.

CONCLUSIONS

Pregnant women who are underweight, overweight or obese, with gestational diabetes mellitus or diabetes mellitus and those who choose vegan/vegetarian diets or are coming from socially disadvantaged areas, should be nutritionally supported to achieve a higher quality diet during pregnancy and/or lactation.

Decreased H3K9 acetylation level of LXRα mediated dexamethasone-induced placental cholesterol transport dysfunction

Due to the insufficient fetal cholesterol synthesis, maternal cholesterol transport through the placenta becomes an important source of fetal cholesterol pool, which is essential for fetal growth and development. This study aimed to investigate the effects of dexamethasone on fetal cholesterol levels, and explore its placental mechanism. Pregnant Wistar rats were injected subcutaneously with dexamethasone (0.8 mg/kg·d) from gestational day 9 to 20. Results showed that dexamethasone increased maternal serum total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C) levels, as well as placental cholesterol synthesis and TC concentration, while reduced fetal birth weight, and serum TC, HDL-C and LDL-C levels. Meanwhile, the expression of placental cholesterol transporters, including low-density lipoprotein receptor (LDLR), scavenger receptor class B type I (SR-B1) and ATP-binding cassette transporter A1 and G1 (ABCA1 and ABCG1) were decreased by dexamethasone. Furthermore, the expression of glucocorticoid receptor (GR) and histone deacetylase 3 (HDAC3) were increased, while the H3K9ac and expression levels of liver X receptor α (LXRα) promoter were reduced. In human trophoblast cell line (BeWo), dexamethasone concentration-dependently decreased the expression levels of LDLR, SR-B1, ABCA1, ABCG1 as well as LXRα. Dexamethasone (2500 nM) induced GR translocation into nucleus and recruited HDAC3. Furthermore, LXRα agonist and GR inhibitor reversed respectively dexamethasone-induced the expression inhibitions of cholesterol transporter and LXRα, and HDAC3 siRNA reversed the H3K9ac level of LXRα promoter and its expression. Together, dexamethasone impaired placental cholesterol transport and eventually decreased fetal cholesterol levels, which is related to the down-regulation of LXRα mediated by GR/HDAC3/H3K9ac signaling.

Programming mediated by fatty acids affects uncoupling protein 1 (UCP-1) in brown adipose tissue

Brown adipose tissue (BAT) has recently been given more attention for the part it plays in obesity. BAT can generate great amounts of heat through thermogenesis by the activation of uncoupling protein 1 (UCP-1), which can be regulated by many environmental factors such as diet. Moreover, the build-up of BAT relates to maternal nutritional changes during pregnancy and lactation. However, at present, there is a limited number of studies looking at maternal nutrition and BAT development, and it seems that the research trend in this field has been considerably declining since the 1980s. There is much to discover yet about the role of different fatty acids on the development of BAT and the activation of UCP-1 during the fetal and the postnatal periods of life. A better understanding of the impact of nutritional intervention on the epigenetic regulation of BAT could lead to new preventive care for metabolic diseases such as obesity. It is important to know in which circumstances lipids could programme BAT during pregnancy and lactation. The modification of maternal dietary fatty acids, amount and composition, during pregnancy and lactation might be a promising strategy for the prevention of obesity in the offspring and future generations.

Prenatal ethanol exposure-induced a low level of foetal blood cholesterol and its mechanism of IGF1-related placental cholesterol transport dysfunction

Clinical researches showed that intrauterine growth retardation (IUGR) foetus had decreased blood cholesterol levels. The present study aimed to confirm that prenatal ethanol exposure (PEE) caused decreased blood cholesterol levels in IUGR foetal rats and elucidate its placental mechanism. Pregnant Wistar rats were intragastrically administrated with ethanol (4 g/kg.d) on gestational days 9-20 (GD9-20). in vivo, PEE increased the levels of total cholesterol (TCH), high-density lipoprotein-cholesterol (HDL-C) and low-density lipoprotein-cholesterol (LDL-C) in maternal serum, whereas decreased them in both female and male foetal serum. Moreover, the expression of cholesterol transport genes, scavenger receptor class B type 1 (SCARB1), low-density lipoprotein receptor (LDLR), ATP binding cassette subfamily A member 1 (ABCA1) and ATP binding cassette subfamily G member 1 (ABCG1) was reduced in female and male placentas in the PEE group. Meanwhile, the proliferation decreased and the apoptosis increased in female and male placentas, and the insulin like growth factor 1 (IGF1) signal pathway was inhibited. in vitro, after being treated with ethanol (15, 30, 60, 120 mM) for 72 h, the expression of cholesterol transport genes was decreased, the apoptosis was increased, the proliferation was decreased and the IGF1 signal pathway was inhibited in BeWo cells, whereas exogenous IGF1 reversed these changes. In conclusion, by inhibiting the IGF1 signal pathway in placentas, PEE induced apoptosis and inhibited proliferation, thus decreased the cholesterol transport in placentas, and eventually leading to low blood cholesterol levels in foetal rats.

Formyl peptide receptor-2 is decreased in foetal growth restriction and contributes to placental dysfunction

STUDY QUESTION

What is the association between placental formyl peptide receptor 2 (FPR2) and trophoblast and endothelial functions in pregnancies affected by foetal growth restriction (FGR)?

SUMMARY ANSWER

Reduced FPR2 placental expression in idiopathic FGR results in significantly altered trophoblast differentiation and endothelial function in vitro.

WHAT IS KNOWN ALREADY

FGR is associated with placental insufficiency, where defective trophoblast and endothelial functions contribute to reduced feto-placental growth.

STUDY DESIGN, SIZE, DURATION

The expression of FPR2 in placental tissues from human pregnancies complicated with FGR was compared to that in gestation-matched uncomplicated control pregnancies (n = 25 from each group). Fpr2 expression was also determined in placental tissues obtained from a murine model of FGR (n = 4). The functional role of FPR2 in primary trophoblasts and endothelial cells in vitro was assessed in diverse assays in a time-dependent manner.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Placentae from third-trimester pregnancies complicated by idiopathic FGR (n = 25) and those from gestation-matched pregnancies with appropriately grown infants as controls (n = 25) were collected at gestation 27-40 weeks. Placental tissues were also collected from a spontaneous CBA/CaH × DBA/2 J murine model of FGR. Placental FPR2/Fpr2 mRNA expression was determined by real-time PCR, while protein expression was examined by immunoblotting and immunohistochemistry. siRNA transfection was used to silence FPR2 expression in primary trophoblasts and in human umbilical vein endothelial cells (HUVEC), and the quantitation of cytokines, chemokines and apoptosis was performed following a cDNA array analyses. Functional effects of trophoblast differentiation were measured using HCGB/β-hCG and syncytin-2 expression as well as markers of apoptosis, tumour protein 53 (TP53), caspase 8, B cell lymphoma 2 (BCL2) and BCL associated X (BAX). Endothelial function was assessed by proliferation, network formation and permeability assays.

MAIN RESULTS AND THE ROLE OF CHANCE

Placental FPR2/Fpr2 expression was significantly decreased in FGR placentae (n = 25, P < 0.05) as well as in murine FGR placentae compared to controls (n = 4, P < 0.05). FPR2 siRNA (siFPR2) in term trophoblasts significantly increased differentiation markers, HCGB and syncytin-2; cytokines, interleukin (IL)-6, CXCL8; and apoptotic markers, TP53, caspase 8 and BAX, but significantly reduced the expression of the chemokines CXCL12 and its receptors CXCR4 and CXCR7; CXCL16 and its receptor, CXCR6; and cytokine, IL-10, compared with control siRNA (siCONT). Treatment of HUVECs with siFPR2 significantly reduced proliferation and endothelial tube formation, but significantly increased permeability of HUVECs.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Reduced expression of placental FPR2/Fpr2 was observed in the third trimester at delivery after development of FGR, suggesting that FPR2 is associated with FGR pregnancies. However, there is a possibility that the decreased placental FPR2 observed in FGR may be a consequence rather than a cause of FGR, although our in vitro functional analyses using primary trophoblasts and endothelial cells suggest that FPR2 may have a direct or indirect regulatory role on trophoblast differentiation and endothelial function in FGR.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first study linking placental FPR2 expression with changes in the trophoblast and endothelial functions that may explain the placental insufficiency observed in FGR.

STUDY FUNDING/COMPETING INTERESTS

P.M. and P.R.E. received funding from the Australian Institute of Musculoskeletal Science, Western Health, St. Albans, Victoria 3021, Australia. M.L. is supported by a Career Development Fellowship from the National Health and Medical Research Council (NHMRC; Grant no. 1047025). Monash Health is supported by the Victorian Government's Operational Infrastructure Support Programme. The authors declare that there is no conflict of interest in publishing this work.

Phospholipids in lipoproteins: compositional differences across VLDL, LDL, and HDL in pregnant women

Objective

The aim of this study was to analyse the differences in the phospholipid composition of very low density (VLDL), low density (LDL) and high density lipoprotein (HDL) monolayers in pregnant lean and obese women.

Methods

LDL, HDL, and VLDL were isolated from plasma samples of 10 lean and 10 obese pregnant women, and their species composition of phosphatidylcholines (PC) and sphingomyelins (SM) was analysed by liquid-chromatography tandem mass-spectrometry. Wilcoxon-Mann-Whitney U test and principal component analysis (PCA) were used to investigate if metabolite profiles differed between the lean/obese group and between lipoprotein species.

Results

No significant differences have been found in the metabolite levels between obese and non-obese pregnant women. The PCA components 1 and 2 separated between LDL, HDL, and VLDL but not between normal weight and obese women. Twelve SM and one PCae were more abundant in LDL than in VLDL. In contrast, four acyl-alkyl-PC and two diacyl-PC were significantly higher in HDL compared to LDL. VLDL and HDL differed in three SM, seven acyl-alkyl-PC and one diacyl-PC (higher values in HDL) and 13 SM (higher in VLDL). We also found associations of some phospholipid species with HDL and LDL cholesterol.

Conclusion

In pregnant women phospholipid composition differs significantly in HDL, LDL and VLDL, similar to previous findings in men and non-pregnant women. Obese and lean pregnant women showed no significant differences in their lipoprotein associated metabolite profile.

Electronic supplementary material

The online version of this article (10.1186/s12944-019-0957-z) contains supplementary material, which is available to authorized users.

Exosomes of pasteurized milk: potential pathogens of Western diseases

Milk consumption is a hallmark of western diet. According to common believes, milk consumption has beneficial effects for human health. Pasteurization of cow's milk protects thermolabile vitamins and other organic compounds including bioactive and bioavailable exosomes and extracellular vesicles in the range of 40-120 nm, which are pivotal mediators of cell communication via systemic transfer of specific micro-ribonucleic acids, mRNAs and regulatory proteins such as transforming growth factor-β. There is compelling evidence that human and bovine milk exosomes play a crucial role for adequate metabolic and immunological programming of the newborn infant at the beginning of extrauterine life. Milk exosomes assist in executing an anabolic, growth-promoting and immunological program confined to the postnatal period in all mammals. However, epidemiological and translational evidence presented in this review indicates that continuous exposure of humans to exosomes of pasteurized milk may confer a substantial risk for the development of chronic diseases of civilization including obesity, type 2 diabetes mellitus, osteoporosis, common cancers (prostate, breast, liver, B-cells) as well as Parkinson's disease. Exosomes of pasteurized milk may represent new pathogens that should not reach the human food chain.

Placental mechanism of prenatal nicotine exposure-reduced blood cholesterol levels in female fetal rats

Clinical studies showed that intrauterine growth retardation (IUGR) neonatus had lower cholesterol concentrations in cord blood, which might be associated with increased risk of metabolic syndrome and cardiovascular diseases in adulthood. We previously observed lower blood cholesterol levels in prenatal nicotine exposure (PNE)-induced IUGR fetal rats, and this study aimed to elucidate the placental mechanism. Pregnant Wistar rats were subcutaneously injected with nicotine (2.0 mg/kg⋅d) on gestational day 9-20. In vivo, PNE increased levels of total cholesterol (TCH), high-density lipoprotein-cholesterol (HDL-C) and low-density lipoprotein-cholesterol (LDL-C) in maternal serum, while decreased levels of TCH and LDL-C in female fetal serum. Meanwhile, the expression of scavenger receptor class B type 1 (SR-B1), ATP-binding cassette transporter A1 (ABCA1) and ATP-binding cassette transporter G1 (ABCG1) were decreased, and the expression of liver X receptor (LXR) α and β were also decreased in female placentas. In vitro, nicotine (0.1-10 μM) reduced the expression of LXRα, LXRβ, SR-B1, ABCA1 and ABCG1 in a concentration dependent manner, which could be annulled by nAChR antagonist and LXR agonist. Taken together, nicotine could inhibit the expression of SR-B1, ABCA1 and ABCG1 via nAChR and LXR α/β in female placentas, finally leading to reduced blood cholesterol levels in fetal rats.

Maternal L-glutamine supplementation during late gestation alleviates intrauterine growth restriction-induced intestinal dysfunction in piglets

Maternal dietary supplementation with L-glutamine (Gln) has been considered as an option to improve fetal growth and to prevent the occurrence of intrauterine growth restriction (IUGR). This study investigated whether maternal Gln supplementation could improve fetal growth as well as the intestinal development during late pregnancy. Sixty pregnant Landrace × Large White multiparous sows were assigned to two groups, either the group fed the control diet or the group with the diet supplemented with 1% Gln from d 85 of gestation until farrowing. One normal body weight piglet and one IUGR piglet were obtained from six litters in each group. Reproductive performance, plasma concentrations of free amino acids and related metabolites as well as piglet growth and tissue indexes were determined. Maternal Gln supplementation during late gestation increased the average birth weight, while decreasing the within-litter variation of newborn piglets. The concentrations of Gln in plasma were lower in IUGR piglets than in normal piglets. Glutamine supplementation enhanced Gln concentrations in maternal and piglet plasma and the piglet jejunum, compared with the Control group. Supplementing Gln suppressed intestinal miR-29a levels, and increased the abundance of extracellular matrix (ECM) and tight junction (TJ) proteins, resulting in increased intestinal weight and improved morphologies of the piglets. Collectively, Gln supplementation to the sow's diet increased fetal growth, decreased the within-litter variation of newborn piglets, and alleviated the IUGR-induced intestinal impairment. These findings suggest the possibility of maternal glutamine supplementation in the prevention and treatment of IUGR in animal production and human medicine.

Endocytosis of lipoproteins

During their metabolism, all lipoproteins undergo endocytosis, either to be degraded intracellularly, for example in hepatocytes or macrophages, or to be re-secreted, for example in the course of transcytosis by endothelial cells. Moreover, there are several examples of internalized lipoproteins sequestered intracellularly, possibly to exert intracellular functions, for example the cytolysis of trypanosoma. Endocytosis and the subsequent intracellular itinerary of lipoproteins hence are key areas for understanding the regulation of plasma lipid levels as well as the biological functions of lipoproteins. Indeed, the identification of the low-density lipoprotein (LDL)-receptor and the unraveling of its transcriptional regulation led to the elucidation of familial hypercholesterolemia as well as to the development of statins, the most successful therapeutics for lowering of cholesterol levels and risk of atherosclerotic cardiovascular diseases. Novel limiting factors of intracellular trafficking of LDL and the LDL receptor continue to be discovered and to provide drug targets such as PCSK9. Surprisingly, the receptors mediating endocytosis of high-density lipoproteins or lipoprotein(a) are still a matter of controversy or even new discovery. Finally, the receptors and mechanisms, which mediate the uptake of lipoproteins into non-degrading intracellular itineraries for re-secretion (transcytosis, retroendocytosis), storage, or execution of intracellular functions, are largely unknown.

Sex-specific Alterations in Serology and the Expression of Liver FATP4 Protein in Offspring Exposed to High-Fat Diet during Pregnancy and/or Lactation

Changes in dietary composition will have a significant impact on the nutritional status of the mother and the offspring. To examine the relevant hormone level changes during lactation and the expression of fatty acid transporters in the placenta and liver under the condition of a high-fat (HF) diet, we established HF animal models and conducted a cross-fostering program to mimic the shift in diet. On gestation day (GD)18, the weight of placenta in the HF group was significantly higher than that in the control group (p < 0.05). HF-fed male pups had a significantly lower serum insulin level, but the same phenomenon was not found in females. On the contrary, serum triacylglycerol (TAG) level presented a tendency to decrease only in female offspring. Oil red O staining showed lipid accumulation in the HF diet offspring livers. The mRNA levels of FATP4 in the placenta in the HF diet group were significantly upregulated compared to the control diet group (p < 0.05). High-fat diet (HFD) consumption also altered the liver mRNA levels of FATP4, SREBP-1, and SCD-1 in the male offspring, while the changes in protein levels of FATP4 were not observed in either sex. In conclusion, maternal HF diet has a profound impact on offspring growth, metabolism, and the risk of metabolic disorders, which would depend on the exposure period of pregnancy and lactation.

Adverse placental effects of valproic acid: Studies in perfused human placentas

OBJECTIVE

In utero exposure to valproic acid (VPA) has been associated with worse pregnancy outcomes compared to all other antiepileptic drugs. We have previously shown that VPA alters the expression of placental transporters for hormones and nutrients in vitro and in pregnant mice. Here, our aim was to characterize the effects of short exposure to VPA on the expression of carriers for compounds essential for fetal development in human placentas ex vivo, under controlled conditions.

METHODS

Placentas were obtained from cesarean deliveries of women with no known epilepsy. Cotyledons were cannulated and perfused in the absence or the presence of VPA (42, 83, or 166 μg/mL; n = 6/group) in the maternal perfusate over 180 minutes. A customized gene panel array was used to analyze the expression of carrier genes in the perfused cotyledons. We additionally measured in the perfused placentas folic acid concentrations and histone acetylation.

RESULTS

VPA significantly altered the mRNA levels of major carriers for folic acid, glucose, choline, thyroid hormones, and serotonin (P < .05) and reduced placental folate concentrations by 25%-35% (P = .059). The effects were observed at therapeutic concentrations sufficient to enhance placental histone acetylation, and some were concentration-dependent.

SIGNIFICANCE

Our results point to the placenta as a novel target of VPA, implying potential involvement of the placenta in VPA's adverse fetal outcomes.

1,25(OH)2D3 Protects Trophoblasts Against Insulin Resistance and Inflammation Via Suppressing mTOR Signaling

Gestational diabetes mellitus (GDM) is the primary cause of maternal and fetal morbidity and mortality. Insulin resistance (IR) is pivotal to GDM pathogenesis, and mammalian target of rapamycin (mTOR) is a critical regulator of GDM. An increasing amount of evidence indicates that vitamin D deficiency is a risk factor for GDM. However, there are few reports on the effect of IR on GDM placentas. The present study aims to verify that 1,25-dihydroxyvitamin D3 (1,25(OH)₂D₃) can ameliorate trophoblast IR by suppressing mTOR signaling. An IR BeWo cell model was established in the presence of high insulin and glucose medium. The IR level and mTOR activation with or without 1,25(OH)₂D₃ treatment were evaluated. The IR cells exhibited excessive mTOR signaling activation, upregulated inflammatory factor levels, and extensive lipid infiltration. However, 1,25(OH)₂D₃ reversed mTOR activation and reduced the IR level and lipid infiltration. In addition, 1,25(OH)₂D₃ treatment in GDM placental explants blocked the aberrant, increased levels of leptin, TNF-α, and IL-6. Therefore, 1,25(OH)₂D₃ treatment protects trophoblasts against high IR mainly through suppressing mTOR signaling, and this mechanism may serve as a potential therapy for patients with GDM.

Insulinotropic nucleobindin-2/nesfatin-1 is dynamically expressed in the haemochorial mouse and human placenta

The placenta is the physiological bridge between mother and fetus and has life-sustaining functions during pregnancy, including metabolic regulation, fetal protection and hormone secretion. Nucleobindin-2 (NUCB2) is a calcium- and DNA-binding protein and precursor of nesfatin-1, a signalling peptide with multiple functions, including regulation of energy homeostasis and glucose transport. These are also key functions of the placenta, yet NUCB2/nesfatin-1 expression has never been comprehensively studied in this organ. In the present study, mouse placental samples from Embryonic Day (E) 7.5 to E17.5 and human chorionic villi from the first and second trimester, as well as term pregnancy, were analysed for NUCB2/nesfatin-1 expression by immunohistochemistry with an antiserum that recognised both NUCB2 and nesfatin-1. From E7.5 to E9.5, NUCB2/nesfatin-1 was expressed in the ectoplacental cone, then parietal trophoblast giant cells and early spongiotrophoblast. At E10.5–12.5, NUCB2/nesfatin-1 expression became detectable in the developing labyrinth. From E12.5 and onwards, NUCB2/nesfatin-1 was expressed in the glycogen trophoblast cells, as well as highly expressed in syncytiotrophoblast, sinusoidal trophoblast giant cells and fetal capillary endothelial cells of the labyrinth. In all trimesters of human pregnancy, NUCB2/nesfatin-1 was highly expressed in syncytiotrophoblast. In addition, there was a significant increase in NUCB2 expression in human primary trophoblast cells induced to syncytialise. Thus, the haemochorial mammalian placenta is a novel source of NUCB2/nesfatin-1 and likely a site of its action, with potential roles in glucose homeostasis and/or nutrient sensing.

Effect of Maternal Obesity on Fetal Growth and Expression of Placental Fatty Acid Transporters

OBJECTIVE

To explore the effects of maternal high-fat (HF) diet-induced obesity on fetal growth and the expression of placental nutrient transporters.

METHODS

Maternal obesity was established in rats by 8 weeks of pre-pregnancy fed HF diet, while rats in the control group were fed normal (CON) diet. Diet-induced obesity (DIO) rats and diet-induced obesity-resistant (DIR) rats were selected according to body weight gain over this period. After copulation, the CON rats were divided into two groups: switched to HF diet (CON-HF group) or maintained on the CON diet (CON-CON group). The DIO rats and DIR rats were maintained on the HF diet throughout pregnancy. Pregnant rats were euthanized at day 21 gestation, fetal and placental weights were recorded, and placental tissue was collected. Reverse transcription-polymerase chain reaction was used to determine mRNA expression of placental nutrient transporters. Protein expression was determined by Western blot.

RESULTS

Average fetal weight of DIO dams was reduced by 6.9%, and the placentas of CON-HF and DIO dams were significantly heavier than the placentas of CON-CON and DIR dams at day 21 of gestation (p<0.05). The fetal/placental weight ratio of DIO dams was significantly reduced compared with the fetal/placental weight ratio of CON-CON dams (p<0.05). The mRNA expression of GLUT-1 and SNAT-2 were not significantly different between groups. The mRNA and protein expression levels of CD36, FATP-1, and FATP-4 in DIO dams were decreased significantly (p<0.05).

CONCLUSION

Maternal obesity induced by a HF diet led to intrauterine growth retardation and down-regulated the expression of placental fatty acid transporters.

Hepar uterinum: a history of ideas on fetal nutrition

The means of fetal nutrition has been debated for over two millennia, with the controversy of oral versus parenteral nutrition already in the Corpus Hippocraticum. In 1587 Aranzio rejected connections between maternal and fetal blood vessels, and coined the term "hepar uterinum" for the placenta. From the 16th to the 18th century, a fervent debate focused on the type and extent of connection between maternal and fetal vessels, which was finally settled by Hunter's injection experiment in 1774. But up to the middle of the 19th century, an important nutritive function was attributed to amniotic fluid. When with the discovery of oxygen the placenta's respiratory function became understood, its nutritional function fell from grace. Most scientists realized reluctantly that the organ had numerous functions. As late as in the 19th century, the advent of microscopy allowed cell theory to develop, and analytical chemistry furthered the understanding of the transport of nutrients across the placenta. The identification of the syncytiotrophoblast made passive diffusion unlikely. Radioisotopes, molecular biology and the fluid mosaic model of the cell membrane revealed active transport mechanisms for nearly all macronutrients.

Maternal BMI and gestational diabetes alter placental lipid transporters and fatty acid composition

INTRODUCTION

Placental fatty acid (FA) uptake and metabolism depend on maternal supply which may be altered when women have a high pre-pregnancy body mass index (BMI) or develop gestational diabetes (GDM). Consequently, an impaired FA transport to the fetus may negatively affect fetal development. While placental adaptation of maternal-fetal glucose transfer in mild GDM has been described, knowledge on placental FA acid metabolism and possible adaptations in response to maternal obesity or GDM is lacking. We aimed to analyze the FA composition and the expression of key genes involved in FA uptake and metabolism in placentas from women with pre-pregnancy normal weight (18.5 ≤ BMI<25 kg/m2), overweight (25 ≤ BMI<30 kg/m²), obesity (BMI ≥ 30 kg/m²), and lean pregnant women with GDM.

METHODS

Placental FA content was determined by gas liquid chromatography. Placental mRNA expression of FA transport proteins (FATP1, FATP4, FATP6), FA binding proteins (FABP3, FABP4, FABP7), FA translocase (FAT/CD36) and enzymes (Endothelial lipase (EL) and lipoprotein lipase (LPL)) were quantified by qRT-PCR.

RESULTS

High pre-pregnancy BMI and GDM were associated with decreased placental FATP1, FATP4, EL and increased FAT/CD36 and FATP6 expressions. LPL mRNA levels and placental total FA content were similar among groups. Specific FA, including some long-chain polyunsaturated FA, were altered.

DISCUSSION

Our results demonstrate that high pre-pregnancy BMI or GDM independently alter mRNA expression levels of genes involved in FA uptake and metabolism and the placental FA profile, which could affect fetal development and long-term health.