The Programming Power of the Placenta

Reactive oxygen species mediated placental oxidative stress, mitochondrial content, and cell cycle progression through mitogen-activated protein kinases in intrauterine growth restricted pigs

Intrauterine growth restriction (IUGR) remains a significant obstacle in pig production; however, information regarding the relationship between reactive oxygen species (ROS)-induced placental dysfunction and IUGR is still unknown. This study aimed to explore the placental redox status, mitochondrial content, cellular progression, and mitogen-activated protein kinase (MAPK) pathways in IUGR. Placental tissues were collected from normal intrauterine gestation (NIUG) and IUGR fetuses at delivery. Compared with the NIUG, placental ROS production, lipid peroxidation, and DNA damage were increased in IUGR. Placental mitochondrial DNA (mtDNA) content and mtDNA-encoded gene expression decreased in IUGR. Moreover, p21 phosphorylation increased, cyclin E expression decreased in IUGR cases, which showed senescence characteristics. Analysis of signaling pathways showed that the ERK1/2 phosphorylation increased whereas the p38 and JNK phosphorylation decreased in IUGR. In cultured porcine trophectoderm (pTr) cells, exogenous H₂O₂ increased intracellular ROS production, decreased cell viability in a dose-dependent manner. Cell cycle distribution was found to arrest in S and G2/M phases. Our findings suggested that IUGR was associated with greater placental ROS and oxidative injury, which might be a factor that resulted in lower mitochondrial content, microvilli loss and senescence, and activation of MAPK pathways.

Fetal sex modifies the effect of maternal macronutrient intake on the incidence of small-for-gestational-age births: a prospective observational cohort study

Background

Maternal macronutrient intake is likely to play a pivotal role in fetoplacental growth. Male fetuses grow faster and their growth is more responsive to maternal size.

Objective

We assessed the role of fetal sex in modifying the effect of maternal macronutrient intake on the risk of small-for-gestational-age (SGA) birth.

Design

This was a prospective, observational cohort study of 2035 births from an urban South Asian Indian population. Maternal intakes of total energy and macronutrients were recorded by validated food-frequency questionnaires. The interaction of trimester 1 macronutrient intake with fetal sex was tested on the outcome of SGA births.

Results

The prevalence of SGA was 28%. Trimester 1 macronutrient composition was high in carbohydrate and low in fat (means ± SDs-carbohydrate: 64.6% ± 5.1%; protein: 11.5% ± 1.1%; and fat: 23.9% ± 4.4% of energy). Higher carbohydrate and lower fat consumption were each associated with an increased risk of SGA [adjusted OR (AOR) per 5% of energy (95% CI): carbohydrate: 1.15 (1.01, 1.32); fat: 0.83 (0.71, 0.97)] specifically among male births (males: n = 1047; females: n = 988). Dietary intake of >70% of energy from carbohydrate was also associated with increased risk (AOR: 1.67; 95% CI: 1.00, 2.78), whereas >25% of energy from fat intake was associated with decreased risk (AOR: 0.61; 95% CI: 0.41, 0.90) of SGA in male births.

Conclusions

Higher carbohydrate and lower fat intakes early in pregnancy were associated with increased risk of male SGA births. Therefore, we speculate that fetal sex acts as a modifier of the role of maternal periconceptional nutrition in optimal fetoplacental growth.

Vitamin D levels, brain volume, and genetic architecture in patients with psychosis

BACKGROUND

Lower vitamin D levels are found in people with schizophrenia and depressive disorders, and also associated with neuroimaging abnormalities such as reduced brain volume in both animals and humans. Reduced whole brain and increased ventricular volume are also systematically reported in schizophrenia. Even though vitamin D deficiency has been proposed as a risk mechanism for schizophrenia there exist no studies to date of the association between vitamin D levels and brain volume in this population. Therefore, we investigated the relationship between vitamin D levels and brain phenotypes in psychotic disorders, and assessed possible interactions with genetic variants in vitamin D receptor (VDR) and other genetic variants that play a role in vitamin D levels in the body.

METHODS

Our sample consisted of 83 psychosis patients and 101 healthy controls. We measured vitamin D levels as serum 25-hydroxyvitamin D. All participants were genotyped and neuroimaging conducted by structural magnetic resonance imaging.

RESULTS

Vitamin D levels were significantly positively associated with peripheral grey matter volume in patients (β 860.6; 95% confidence interval (CI) 333.4-1466, p < .003). A significant interaction effect of BSML marker (rs1544410) was observed to mediate the association between patient status and both white matter volume (β 23603.3; 95% CI 2732.8-48708.6, p < .05) and whole brain volume (β 46670.6, 95% CI 8817.8-93888.3, p < .04). Vitamin D did not predict ventricular volume, which rather was associated with patient status (β 4423.3, 95% CI 1583.2-7267.8p < .002) and CYP24A1 marker (rs6013897) (β 2491.5, 95% CI 269.7-4978.5, p < .04).

CONCLUSIONS

This is the first study of the association between vitamin D levels and brain volume in patients with psychotic disorders that takes into account possible interaction with genetic polymorphisms. The present findings warrant replication in independent samples.

Fetal undernutrition, placental insufficiency, and pancreatic β-cell development programming in utero

The prevalence of obesity and type 2 (T2D) diabetes is a major health concern in the United States and around the world. T2D is a complex disease characterized by pancreatic β-cell failure in association with obesity and insulin resistance in peripheral tissues. Although several genes associated with T2D have been identified, it is speculated that genetic variants account for only <10% of the risk for this disease. A strong body of data from both human epidemiological and animal studies shows that fetal nutrient factors in utero confer significant susceptibility to T2D. Numerous studies done in animals have shown that suboptimal maternal environment or placental insufficiency causes intrauterine growth restriction (IUGR) in the fetus, a critical factor known to predispose offspring to obesity and T2D, in part by causing permanent consequences in total functional β-cell mass. This review will focus on the potential contribution of the placenta in fetal programming of obesity and TD and its likely impact on pancreatic β-cell development and growth.

Role of the Macrophage Migration Inhibitory Factor (MIF) in the survival of first trimester human placenta under induced stress conditions

Macrophage Migration Inhibitory Factor (MIF) is a multifunctional molecule highly secreted by human placenta mainly in the early phases of pregnancy. Studies in different cells show that MIF is a pro-survival factor by binding to its receptor CD74. By using the in vitro model of placental explants from first trimester pregnancy, we investigated the role of MIF in the survival of placental cells under induced stress conditions that promote apoptosis or mimic the hypoxia/re-oxygenation (H/R) injury that placenta could suffer in vivo. We demonstrated that recombinant MIF (rMIF) treatment was able to reduce caspase-3 activation when cultures were challenged with the apoptosis-inducer Carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP) while, in the cultures exposed to H/R, the treatment with rMIF did not show any effect. However, a significant increase in caspase-3 and caspase-8 activation was found when H/R-exposed cultures, were treated with anti-MIF or anti-CD74 antibody. We also observed that under H/R, a significant amount of endogenous MIF was released into the medium, which could account for the lack of effect of rMIF added to the cultures. Our results demonstrate for the first time that the MIF/CD74 axis contributes to maintain trophoblast homeostasis, by preventing abnormal apoptotic death.

Pomegranate Juice Supplementation Alters Utero-Placental Vascular Function and Fetal Growth in the eNOS-/- Mouse Model of Fetal Growth Restriction

The eNOS^−/− mouse provides a well-characterized model of fetal growth restriction (FGR) with altered uterine and umbilical artery function and reduced utero- and feto-placental blood flow. Pomegranate juice (PJ), which is rich in antioxidants and bioactive polyphenols, has been posited as a beneficial dietary supplement to promote cardiovascular health. We hypothesized that maternal supplementation with PJ will improve uterine and umbilical artery function and thereby enhance fetal growth in the eNOS^−/− mouse model of FGR. Wild type (WT, C57Bl/6J) and eNOS^−/− mice were supplemented from E12.5-18.5 with either PJ in their drinking water or water alone. At E18.5 uterine (UtA) and umbilical (UmbA) arteries were isolated for study of vascular function, fetuses and placentas were weighed and fetal biometric measurements taken. PJ supplementation significantly increased UtA basal tone (both genotypes) and enhanced phenylephrine-induced contraction in eNOS^−/− but not WT mice. Conversely PJ significantly reduced UtA relaxation in response to both acetylcholine (Ach) and sodium nitroprusside (SNP), endothelium dependent and independent vasodilators respectively from WT but not eNOS^−/− mice. UmbA sensitivity to U46619-mediated contraction was increased by PJ supplementation in WT mice; PJ enhanced contraction and relaxation of UmbA to Ach and SNP respectively in both genotypes. Contrary to our hypothesis, the changes in artery function induced by PJ were not associated with an increase in fetal weight. However, PJ supplementation reduced litter size and fetal abdominal and head circumference in both genotypes. Collectively the data do not support maternal PJ supplementation as a safe or effective treatment for FGR.

GENDER-SPECIFIC INFLUENCE OF Aу MUTATION ON PROGENY METABOLIC PHENOTYPE, FETAL GROWTH AND PLACENTAL GENE EXPRESSION IN MICE

Obesity during pregnancy increases the risk of obesity in offspring. To correct the offspring development in obese mothers, it is necessary to reveal the molecular mechanisms that mediate the influence of the maternal environment on the offspring ontogenesis. Leptin levels increase with obesity. In C57Bl mice, the Ауmutation is associated with elevated blood levels of leptin in pregnant females and exerts a gender-specific effect on the metabolic phenotype of mature offspring. Aim: to study the influence of Ауmutation on sensitivity to diet-induced obesity in male and female offspring, on fetal and placental weight and on the expression of genes in the placentas of the fetuses of different sexes. Body weight and food intake on a standard and an obesogenic diet, fetal and placental weights on pregnancy days 13 and 18, and gene expression of glucose transporters (GLUT1, GLUT3), neutral amino acid transporters (SNAT1, SNAT2, SNAT4), insulin-like growth factor 2 IGF2 and its receptor IGF2R were measured in male and female offspring of и ɑ/ɑ (control) and Ау/ɑ mothers. Aymutation influenced the body weight only in male offspring, which consumed a standard diet, and did not influence obesity development in both male and female offspring. The weight of fetuses and placentas in Ау/ɑ as compared to ɑ/ɑ  females was reduced on day 13 of pregnancy and was not different on day 18. On day 13 of pregnancy, the mRNA levels of the examined genes did not differ in placentas of male and female fetuses in ɑ/ɑ  females. In Ау/ɑ females, the gene expression of GLUT1, GLUT3, SNAT1 and SNAT4 was reduced in female placentas compared to male placentas. The results suggest that the sex-specific transcription response of placentas to elevated leptin levels in pregnant Ау/ɑ females can mediate the gender-specific impact of Ауmutation on the offspring metabolism in postnatal life.

Review shows that maternal obesity induces serious adverse neonatal effects and is associated with childhood obesity in their offspring

AIM

Obesity at the start of pregnancy has been rising worldwide, increasing the risk of maternal complications. We reviewed the independent effects of maternal obesity during pregnancy on neonatal adverse outcomes and the risk of childhood obesity and adverse cardio-metabolic profiles.

METHODS

We searched MEDLINE for papers published in English between December 2007 and November 2017, focusing primarily on human studies published in the last five years. However, we also chose to highlight examples derived from model animals that could bring mechanistic insight and preventive and therapeutic avenues.

RESULTS

Our review showed that maternal obesity had independent effects on neonatal adverse outcomes such as macrosomia, perinatal mortality and birth defects. Maternal obesity alone increased the risks for adverse neonatal outcomes, including macrosomia, perinatal mortality, induced preterm birth and birth defects. In association with excess gestational weight gain, mainly early in pregnancy, increased the risks of childhood obesity, higher fat mass and, to a smaller extent, adverse cardio-metabolic profiles. Animal models highlighted sexually dimorphic responses to maternal obesity.

CONCLUSION

Maternal obesity induced serious adverse neonatal effects and was associated with childhood obesity in their offspring. The peri-conceptional period is critical for metabolic programming, and obese women need close monitoring from conception.

Near to One's Heart: The Intimate Relationship Between the Placenta and Fetal Heart

The development of the fetal heart is exquisitely controlled by a multitude of factors, ranging from humoral to mechanical forces. The gatekeeper regulating many of these factors is the placenta, an external fetal organ. As such, resistance within the placental vascular bed has a direct influence on the fetal circulation and therefore, the developing heart. In addition, the placenta serves as the interface between the mother and fetus, controlling substrate exchange and release of hormones into both circulations. The intricate relationship between the placenta and fetal heart is appreciated in instances of clinical placental pathology. Abnormal umbilical cord insertion is associated with congenital heart defects. Likewise, twin-to-twin transfusion syndrome, where monochorionic twins have unequal sharing of their placenta due to inter-twin vascular anastomoses, can result in cardiac remodeling and dysfunction in both fetuses. Moreover, epidemiological studies have suggested a link between placental phenotypic traits and increased risk of cardiovascular disease in adult life. To date, the mechanistic basis of the relationships between the placenta, fetal heart development and later risk of cardiac dysfunction have not been fully elucidated. However, studies using environmental exposures and gene manipulations in experimental animals are providing insights into the pathways involved. Likewise, surgical instrumentation of the maternal and fetal circulations in large animal species has enabled the manipulation of specific humoral and mechanical factors to investigate their roles in fetal cardiac development. This review will focus on such studies and what is known to date about the link between the placenta and heart development.

Maternal obesity increases the risk of metabolic disease and impacts renal health in offspring

Obesity, together with insulin resistance, promotes multiple metabolic abnormalities and is strongly associated with an increased risk of chronic disease including type 2 diabetes (T2D), hypertension, cardiovascular disease, non-alcoholic fatty liver disease (NAFLD) and chronic kidney disease (CKD). The incidence of obesity continues to rise in astronomical proportions throughout the world and affects all the different stages of the lifespan. Importantly, the proportion of women of reproductive age who are overweight or obese is increasing at an alarming rate and has potential ramifications for offspring health and disease risk. Evidence suggests a strong link between the intrauterine environment and disease programming. The current review will describe the importance of the intrauterine environment in the development of metabolic disease, including kidney disease. It will detail the known mechanisms of fetal programming, including the role of epigenetic modulation. The evidence for the role of maternal obesity in the developmental programming of CKD is derived mostly from our rodent models which will be described. The clinical implication of such findings will also be discussed.

Placental miR-340 mediates vulnerability to activity based anorexia in mice

Anorexia nervosa (AN) is a devastating eating disorder characterized by self-starvation that mainly affects women. Its etiology is unknown, which impedes successful treatment options leading to a limited chance of full recovery. Here, we show that gestation is a vulnerable window that can influence the predisposition to AN. By screening placental microRNA expression of naive and prenatally stressed (PNS) fetuses and assessing vulnerability to activity-based anorexia (ABA), we identify miR-340 as a sexually dimorphic regulator involved in prenatal programming of ABA. PNS caused gene-body hypermethylation of placental miR-340, which is associated with reduced miR-340 expression and increased protein levels of several target transcripts, GR, Cry2 and H3F3b. MiR-340 is linked to the expression of several nutrient transporters both in mice and human placentas. Using placenta-specific lentiviral transgenes and embryo transfer, we demonstrate the key role miR-340 plays in the mechanism involved in early life programming of ABA.

Anorexia nervosa is characterised by self-starvation but its etiology is not completely understood. Here the authors describe how prenatal stress can induce activity-based anorexia in the offspring during early adulthood by upregulating miR-340 expression in the placenta that affects expression of nutrient transporters.

nAChRs-ERK1/2-Egr-1 signaling participates in the developmental toxicity of nicotine by epigenetically down-regulating placental 11β-HSD2

Impaired placental 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) activity which inactivates maternal glucocorticoids is associated with poor fetal growth and a higher risk of chronic diseases in adulthood. This study aimed to elucidate the epigenetically regulatory mechanism of nicotine on placental 11β-HSD2 expression. Pregnant Wistar rats were administered 1.0 mg/kg nicotine subcutaneously twice a day from gestational day 9 to 20. The results showed that prenatal nicotine exposure increased corticosterone levels in the placenta and fetal serum, disrupted placental morphology and endocrine function, and reduced fetal bodyweight. Meanwhile, histone modification abnormalities (decreased acetylation and increased di-methylation of histone 3 Lysine 9) on the HSD11B2 promoter and lower-expression of 11β-HSD2 were observed. Furthermore, the expression of nicotinic acetylcholine receptor (nAChR) α4/β2, the phosphorylation of extracellular regulated kinase 1/2 (ERK1/2) and Ets-like protein-1 (Elk-1), and the expression of early growth response-1 (Egr-1) were increased in the nicotine groups. In human BeWo cells, nicotine decreased 11β-HSD2 expression, increased nAChRα9 expression, and activated ERK1/2/Elk-1/Egr-1 signaling in the concentration (0.1-10 μM)-dependent manner. Antagonism of nAChRs, inhibition of ERK1/2 and Egr-1 knockdown by siRNA were able to block/abrogate the effects of nicotine on histone modification and expression of 11β-HSD2. Taken together, nicotine can impair placental structure and function, and induce fetal developmental toxicity. The underlying mechanism involves histone modifications and down-regulation of 11β-HSD2 through nAChRs/ERK1/2/Elk-1/Egr-1 signaling, which increases active glucocorticoids levels in the placenta and fetus, and eventually inhibits the fetal development.

Acute Drug Effects on the Human Placental Tissue: The Development of a Placental Murine Xenograft Model

OBJECTIVE

A pilot study was conducted to establish a human placental xenograft, which could serve as a model to evaluate the effect of toxic exposures during pregnancy.

STUDY DESIGN

The protocol consisted of engraftment of third-trimester human placental tissue in immunocompromised mice, after induction of a pseudo-pregnancy state by ovariectomy and progesterone supplementation. To validate the model, the placental tissue before and after engraftment was examined by immunohistochemistry, fluorescence-activated cell sorting (FACS), single-nucleotide polymorphism (SNP) genotyping, and whole transcriptome sequencing (WTSS). The human chorion gonadotropin (hCG) production in serum and urine was examined by enzyme-linked immunosorbent assay.

RESULTS

Microscopic evaluation of the placental tissue before and after engraftment revealed a stable morphology and preserved histological structure of the human tissue. Viable trophoblast was present after engraftment and remained stable over time. Vascularization and hormonal secretion (hCG) were present till 3 weeks after engraftment. Thirty-one SNPs were equally present, and there was a stable expression level for 56 451 genes evaluated by whole transcriptome sequencing.

CONCLUSION

Although this human placental xenograft model cannot copy the unique uterine environment in which the placenta develops and interacts between the mother and the fetus, it could be a suitable tool to evaluate the acute impact and adaptive processes of the placental tissue to environmental changes.

Regulating needs: Exploring the role of insulin-like growth factor-2 signalling in materno-fetal resource allocation

During pregnancy, the fetus requires nutrients supplied by the mother to grow and develop. However, the mother also requires sufficient resources to support the pregnancy, as well as, to maintain her health. Failure to regulate resource allocation between the mother and fetus can lead to pregnancy complications with immediate and life-long consequences for maternal and offspring health. This review explores the role of insulin-like growth factor (IGF)-2 in regulating materno-fetal resource allocation, particularly via its regulation of placental development and function.

Assessment of Placental Transport Function in Studies of Disease Programming

Environmental conditions during pregnancy affect fetal growth and development and program the offspring for poor future health. These effects may be mediated by the placenta, which develops to transfer nutrients from the mother to the fetus for growth. The ability to measure the unidirectional maternofetal transfer of non-metabolizable radio-analogues of glucose and amino acid by the placenta in vivo has thus been invaluable to our understanding of the regulation of fetal growth, particularly in small animal models. Herein, I describe the method by which in vivo placental transfer function can be quantified in the mouse, an animal model widely used in studies of in utero disease programming.

Zinc is a critical regulator of placental morphogenesis and maternal hemodynamics during pregnancy in mice

Zinc is an essential micronutrient in pregnancy and zinc deficiency impairs fetal growth. We used a mouse model of moderate zinc deficiency to investigate the physiological mechanisms by which zinc is important to placental morphogenesis and the maternal blood pressure changes during pregnancy. A 26% reduction in circulating zinc (P = 0.005) was exhibited in mice fed a moderately zinc-deficient diet. Zinc deficiency in pregnancy resulted in an 8% reduction in both near term fetal and placental weights (both P < 0.0001) indicative of disrupted placental development and function. Detailed morphological analysis confirmed changes to the placental labyrinth microstructure. Continuous monitoring of maternal mean arterial pressure (MAP) revealed a late gestation decrease in the zinc-deficient dams. Differential expression of a number of regulatory genes within maternal kidneys supported observations on MAP changes in gestation. Increased MAP late in gestation is required to maintain perfusion of multiple placentas within rodent pregnancies. Decreased MAP within the zinc-deficient dams implies reduced blood flow and nutrient delivery to the placenta. These findings show that adequate zinc status is required for correct placental morphogenesis and appropriate maternal blood pressure adaptations to pregnancy. We conclude that insufficient maternal zinc intake from before and during pregnancy is likely to impact in utero programming of offspring growth and development largely through effects to the placenta and maternal cardiovascular system.

DNA Methylation Divergence and Tissue Specialization in the Developing Mouse Placenta

The placental epigenome plays a vital role in regulating mammalian growth and development. Aberrations in placental DNA methylation are linked to several disease states, including intrauterine growth restriction and preeclampsia. Studying the evolution and development of the placental epigenome is critical to understanding the origin and progression of such diseases. Although high-resolution studies have found substantial variation between placental methylomes of different species, the nature of methylome variation has yet to be characterized within any individual species. We conducted a study of placental DNA methylation at high resolution in multiple strains and closely related species of house mice (Mus musculus musculus, Mus m. domesticus, and M. spretus), across developmental timepoints (embryonic days 15-18), and between two distinct layers (labyrinthine transport and junctional endocrine). We observed substantial genome-wide methylation heterogeneity in mouse placenta compared with other differentiated tissues. Species-specific methylation profiles were concentrated in retrotransposon subfamilies, specifically RLTR10 and RLTR20 subfamilies. Regulatory regions such as gene promoters and CpG islands displayed cross-species conservation, but showed strong differences between layers and developmental timepoints. Partially methylated domains exist in the mouse placenta and widen during development. Taken together, our results characterize the mouse placental methylome as a highly heterogeneous and deregulated landscape globally, intermixed with actively regulated promoter and retrotransposon sequences.

Involvement of leptin in the molecular physiology of the placenta

Leptin is a homeostatic regulator in the placenta where it promotes proliferation, protein synthesis and the expression of tolerogenic maternal response molecules such as HLA-G. Leptin also exerts an anti-apoptotic action in placenta controlling the expression of p53 master cell cycle regulator under different stress conditions. On the other hand, leptin is an integrative target of different placental stimuli. The expression of leptin in placenta is regulated by hCG, insulin, steroids, hypoxia and many other growth hormones, suggesting that it might have an important endocrine function in the trophoblastic cells. The leptin expression is induced involving the cAMP/PKA or cAMP/Epac pathways which have profound actions upon human trophoblast function. The activation of PI3K and MAPK pathways also participates in the leptin expression. Estrogens play a central role during pregnancy, particularly 17β-estradiol upregulates the leptin expression in placental cells through genomic and non-genomic actions. The leptin promoter analysis reveals specific elements that are active in placental cells. The transcription factors CREB, AP1, Sp1, NFκB and the coactivator CBP are involved in the placental leptin expression. Moreover, placental leptin promoter is a target of epigenetic marks such as DNA methylation and histone acetylation that regulates not only the leptin expression in placenta during pregnancy but also determines the predisposition of acquiring adult metabolism diseases. Taken together, all these results allow a better understanding of leptin function and regulatory mechanisms of leptin expression in human placental trophoblasts, and support the importance of leptin during pregnancy and in programming adult health.

Decreased insulin secretion in pregnant rats fed a low protein diet

Low protein (LP) diet during pregnancy leads to reduced plasma insulin levels in rodents, but the underlying mechanisms remain unclear. Glucose is the primary insulin secretagogue, and enhanced glucose-stimulated insulin secretion (GSIS) in beta cells contributes to compensation for insulin resistance and maintenance of glucose homeostasis during pregnancy. In this study, we hypothesized that plasma insulin levels in pregnant rats fed LP diet are reduced due to disrupted GSIS of pancreatic islets. We first confirmed reduced plasma insulin levels, then investigated in vivo insulin secretion by glucose tolerance test and ex vivo GSIS of pancreatic islets in the presence of glucose at different doses, and KCl, glibenclamide, and L-arginine. Main findings include (1) plasma insulin levels were unaltered on day 10, but significantly reduced on days 14-22 of pregnancy in rats fed LP diet compared to those of control (CT) rats; (2) insulin sensitivity was unchanged, but glucose intolerance was more severe in pregnant rats fed LP diet; (3) GSIS in pancreatic islets was lower in LP rats compared to CT rats in the presence of glucose, KCl, and glibenclamide, and the response to L-arginine was abolished in LP rats; and (4) the total insulin content in pancreatic islets and expression of Ins2 were reduced in LP rats, but expression of Gcg was unaltered. These studies demonstrate that decreased GSIS in beta cells of LP rats contributes to reduced plasma insulin levels, which may lead to placental and fetal growth restriction and programs hypertension and other metabolic diseases in offspring.

Alternate paradigms on Zika virus-related complications: An analytical review

The proportion of the reported cases of Zika virus (ZIKV) infection reached the status of a pandemic. Numerous studies are being conducted on the isolation of ZIKV strains from various epidemics, diagnosis of the infections, various animal models and cell culture designs to study the pathogenesis of ZIKV in the attempts to find an effective ZIKV vaccine. This review focuses upon the 'Off-Spectrum' body of studies which analyses the epidemiology, pathogenesis and other attributes of ZIKV in the light of various dissident hypotheses.

Chorionic vascular "fit" in the human placenta: Relationship to fetoplacental outcomes

BACKGROUND

Novel measures of the chorionic plate and vessels are used to test the hypothesis that variation in placental structure is correlated with reduced birth weight (BW) independent of placental weight (PW), suggesting functionally compromised placentas.

METHODS

916 mothers recruited to the Pregnancy, Infection and Nutrition Study delivering singleton live born infants at >30 gestational weeks had placentas collected, digitally photographed and weighed prior to formalin fixation. The fetal-placental weight ratio (FPR) was calculated as birthweight/placental weight. Beta (beta) was calculated as ln(PW)/ln(BW). Chorionic disk perimeter was traced and chorionic surface shape (CS) area was calculated. "Fit" was defined as the ratio of the area of the vascular to the full chorionic surface area. The sites at which chorionic vessels dived beneath the chorionic surface were marked to calculate the chorionic surface vessel (CV) area. The centroids of shapes, the distance between centroids and other measures of shape irregularities were calculated. Principal components analysis (PCA) created three independent factors. Factors were used in regression analyses to explore relations to birth weight, trimmed placental weight, FPR, and beta. Specific measures of shape irregularity were also examined in regression analyses for interrelationships and to predict birth weight, placental weight, FPR, and beta.

RESULTS

Variables related to disk size (CS area, perimeter) were correlated with BW, GA, trimmed PW and beta. "Fit" (the ratio of CV area to CS area), measures of shape irregularities, and the distance between the cord insertion and the centroids of surface and vascular areas were also correlated with one or more of the clinical outcome variables. PCA yielded three factors that had independent effects on birth weight, placental weight, the fetal-placental weight ratio, and beta (each p < 0.0001). Addition of GA did not alter the factors' associations with outcomes. Chorionic "fit" (ratio of areas), also included within the factor analysis, was a positive predictor of birth weight (p = 0.005) and FPR (p = 0.002) and a negative predictor of beta (p = 0.01). Fit was statistically significantly associated with greater distances between the umbilical cord insertion site and the CS (p < 0.001) and CV centroids (p < 0.001), and to lesser displacement between CS and CV centroids (p < 0.001).

CONCLUSIONS

Measures of CS and CV account for variation in placental efficiency defined by beta, independent of GA. Macroscopic placenta measurements can identify suboptimal placental development.

Treating the dysfunctional placenta

Placental dysfunction underlies major obstetric diseases such as pre-eclampsia and fetal growth restriction (FGR). Whilst there has been a little progress in prophylaxis, there are still no treatments for placental dysfunction in normal obstetric practice. However, a combination of increasingly well-described in vitro systems for studying the human placenta, together with the availability of more appropriate animal models of pre-eclampsia and FGR, has facilitated a recent surge in work aimed at repurposing drugs and therapies, developed for other conditions, as treatments for placental dysfunction. This review: (1) highlights potential candidate drug targets in the placenta - effectors of improved uteroplacental blood flow, anti-oxidants, heme oxygenase induction, inhibition of HIF, induction of cholesterol synthesis pathways, increasing insulin-like growth factor II availability; (2) proposes an experimental pathway for taking a potential drug or treatment for placental dysfunction from concept through to early phase clinical trials, utilizing techniques for studying the human placenta in vitro and small animal models, particularly the mouse, for in vivo studies; (3) describes the data underpinning sildenafil citrate and adenovirus expressing vascular endothelial growth as potential treatments for placental dysfunction and summarizes recent research on other potential treatments. The importance of sharing information from such studies even when no effect is found, or there is an adverse outcome, is highlighted. Finally, the use of adenoviral vectors or nanoparticle carriers coated with homing peptides to selectively target drugs to the placenta is highlighted: such delivery systems could improve efficacy and reduce the side effects of treating the dysfunctional placenta.

Nanoparticles and female reproductive system: how do nanoparticles affect oogenesis and embryonic development

Along with the increasing application of nanoparticles (NPs) in many walks of life, environmental exposure to NPs has raised considerable health concerns. When NPs enter a pregnant woman’s body through inhalation, venous injection, ingestion or skin permeation, maternal toxic stress reactions such as reactive oxygen species (ROS), inflammation, apoptosis and endocrine dyscrasia are induced in different organs, particularly in the reproductive organs. Recent studies have shown that NPs disturb the developing oocyte by invading the protective barrier of theca cells, granulosa cell layers and zona pellucida. NPs disrupt sex hormone levels through the hypothalamic–pituitary-gonadal axis or by direct stimulation of secretory cells, such as granule cells, follicle cells, thecal cells and the corpus luteum. Some NPs can cross the placenta into the fetus by passive diffusion or endocytosis, which can trigger fetal inflammation, apoptosis, genotoxicity, cytotoxicity, low weight, reproductive deficiency, nervous damage, and immunodeficiency, among others. The toxicity of these NPs depend on their size, dosage, shape, charge, material and surface-coating. We summarize new findings on the toxic effect of various NPs on the ovary and on oogenesis and embryonic development. Meanwhile, we highlight the problems that need to be studied in the future. This manuscript will also provide valuable guidelines for protecting the female reproductive system from the toxicity of NPs and provide a certain reference value for NP application in the area of ovarian diseases.

Placental phenotype and the insulin-like growth factors: resource allocation to fetal growth

The placenta is the main determinant of fetal growth and development in utero. It supplies all the nutrients and oxygen required for fetal growth and secretes hormones that facilitate maternal allocation of nutrients to the fetus. Furthermore, the placenta responds to nutritional and metabolic signals in the mother by altering its structural and functional phenotype, which can lead to changes in maternal resource allocation to the fetus. The molecular mechanisms by which the placenta senses and responds to environmental cues are poorly understood. This review discusses the role of the insulin-like growth factors (IGFs) in controlling placental resource allocation to fetal growth, particularly in response to adverse gestational environments. In particular, it assesses the impact of the IGFs and their signalling machinery on placental morphogenesis, substrate transport and hormone secretion, primarily in the laboratory species, although it draws on data from human and other species where relevant. It also considers the role of the IGFs as environmental signals in linking resource availability to fetal growth through changes in the morphological and functional phenotype of the placenta. As altered fetal growth is associated with increased perinatal morbidity and mortality and a greater risk of developing adult-onset diseases in later life, understanding the role of IGFs during pregnancy in regulating placental resource allocation to fetal growth is important for identifying the mechanisms underlying the developmental programming of offspring phenotype by suboptimal intrauterine growth.

The health outcomes of human offspring conceived by assisted reproductive technologies (ART)

Concerns have been raised about the health and development of children conceived by assisted reproductive technologies (ART) since 1978. Controversially, ART has been linked with adverse obstetric and perinatal outcomes, an increased risk of birth defects, cancers, and growth and development disorders. Emerging evidence suggests that ART treatment may also predispose individuals to an increased risk of chronic ageing related diseases such as obesity, type 2 diabetes and cardiovascular disease. This review will summarize the available evidence on the short-term and long-term health outcomes of ART singletons, as multiple pregnancies after multiple embryos transfer, are associated with low birth weight and preterm delivery, which can separately increase risk of adverse postnatal outcomes, and impact long-term health. We will also examine the potential factors that may contribute to these health risks, and discuss underlying mechanisms, including epigenetic changes that may occur during the preimplantation period and reprogram development in utero, and adult health, later in life. Lastly, this review will consider the future directions with the view to optimize the long-term health of ART children.

Vitamin D deficiency and impaired placental function: potential regulation by glucocorticoids?

Maternal vitamin D deficiency has been implicated in a range of pregnancy complications including preeclampsia, preterm birth and intrauterine growth restriction. Some of these adverse outcomes arise from alterations in placental function. Indeed, vitamin D appears critical for implantation, inflammation, immune function and angiogenesis in the placenta. Despite these associations, absence of the placental vitamin D receptor in mice provokes little effect. Thus, interactions between maternal and fetal compartments are likely crucial for instigating adverse placental changes. Indeed, maternal vitamin D deficiency elicits changes in glucocorticoid-related parameters in pregnancy, which increase placental and fetal glucocorticoid exposure. As in utero glucocorticoid excess has a well-established role in eliciting placental dysfunction and fetal growth restriction, this review proposes that glucocorticoids are an important consideration when understanding the impact of vitamin D deficiency on placental function and fetal development.

Competition for Materno-Fetal Resource Partitioning in a Rabbit Model of Undernourished Pregnancy

The major goal of animal production is to obtain abundant and healthy meat for consumers. Maternal food restriction (MFR) is often applied in farms to reduce production costs. However, the suitability of MFR in livestock animals is questionable, as this management may compromise maternal fitness due to a severe negative energetic balance and can induce Intrauterine Growth Restriction (IUGR) and prenatal programming in the offspring. Here, we sought to determine, using pregnant rabbits, the consequences of MFR on maternal endocrine and metabolic status and conceptus development. Pregnant dams were distributed into three groups: CONTROL (ad libitum feeding throughout the entire pregnancy; mean pregnancy length being around 31 days), UNDERFED (50% MFR during the entire pregnancy) and EARLY-UNDERFED (50% MFR only during the preimplantation period, Days 0–7). Maternal leptin concentrations and glycemic and lipid profiles were determined throughout pregnancy, whilst conceptus development was assessed ex-vivo at Day 28. Placental parameters were determined by macroscopic and histological evaluations and apoptotic assessments (TUNEL and Caspase-3). The main results of the study showed that, despite MFR altered maternal plasma lipid concentration (P<0.05), there were no effects on maternal bodyweight, plasma leptin concentration or glycemic profile. Fetal crown-rump lengths were reduced in both undernourished groups (P<0.001), but a significant reduction in fetal weight was only observed in the UNDERFED group (P<0.001). Growth in both undernourished groups was asymmetrical, with reduced liver weight (P<0.001) and significantly increased brain: fetal weight-ratio (P<0.001) and brain: liver weight-ratio (P<0.001) when compared to the CONTROL group. A significant reduction in placental weight was only observed in the UNDERFED group (P<0.001), despite both undernourished groups showing higher apoptotic rates at decidua and labyrinth zone (P<0.05) than the CONTROL group. Thus, these groups evidenced signs of placental degeneration, necrosis and stromal collapse. In summary, MFR may encourage the mother to make strategic decisions to safeguard her metabolic status and fitness at the expense of growth reduction in the litter, resulting in enhanced apoptotic and pathological processes at placental level and IUGR.

Corticotropin-Releasing Hormone As the Homeostatic Rheostat of Feto-Maternal Symbiosis and Developmental Programming In Utero and Neonatal Life

A balanced interaction between the homeostatic mechanisms of mother and the developing organism during pregnancy and in early neonatal life is essential in order to ensure optimal fetal development, ability to respond to various external and internal challenges, protection from adverse programming, and safeguard maternal care availability after parturition. In the majority of pregnancies, this relationship is highly effective resulting in successful outcomes. However, in a number of pathological settings, perturbations of the maternal homeostasis disrupt this symbiosis and initiate adaptive responses with unpredictable outcomes for the fetus or even the neonate. This may lead to development of pathological phenotypes arising from developmental reprogramming involving interaction of genetic, epigenetic, and environmental-driven pathways, sometimes with acute consequences (e.g., growth impairment) and sometimes delayed (e.g., enhanced susceptibility to disease) that last well into adulthood. Most of these adaptive mechanisms are activated and controlled by hormones of the hypothalamo-pituitary adrenal axis under the influence of placental steroid and peptide hormones. In particular, the hypothalamic peptide corticotropin-releasing hormone (CRH) plays a key role in feto-maternal communication by orchestrating and integrating a series of neuroendocrine, immune, metabolic, and behavioral responses. CRH also regulates neural networks involved in maternal behavior and this determines efficiency of maternal care and neonate interactions. This review will summarize our current understanding of CRH actions during the perinatal period, focusing on the physiological roles for both mother and offspring and also how external challenges can alter CRH actions and potentially impact on fetus/neonate health.

Cross-fostering: Elucidating the effects of gene×environment interactions on phenotypic development

Cross-fostering of litters from soon after birth until weaning is a valuable tool to study the ways in which gene×environment interactions program the development of neural, physiological and behavioral characteristics of mammalian species. In laboratory mice and rats, the primary focus of this review, cross-fostering of litters between mothers of different strains or treatment groups (intraspecific) or between mothers of different species (interspecific) has been conducted over the past 9 decades. Areas of particular interest have included maternal effects on emotionality, social preferences, responses to stressful stimulation, nutrition and growth, blood pressure regulation, and epigenetic effects on brain development and behavior. Results from these areas of research highlight the critical role of the postnatal maternal environment in programming the development of offspring phenotypic characteristics. In addition, experimental paradigms that have included cross-fostering have permitted investigators to tease apart prenatal versus postnatal effects of various treatments on offspring development and behavior.

Maternal and fetal genomes interplay through phosphoinositol 3-kinase(PI3K)-p110α signaling to modify placental resource allocation

Pregnancy success and life-long health depend on a cooperative interaction between the mother and the fetus in the allocation of resources. As the site of materno-fetal nutrient transfer, the placenta is central to this interplay; however, the relative importance of the maternal versus fetal genotypes in modifying the allocation of resources to the fetus is unknown. Using genetic inactivation of the growth and metabolism regulator, Pik3ca (encoding PIK3CA also known as p110α, α/+), we examined the interplay between the maternal genome and the fetal genome on placental phenotype in litters of mixed genotype generated through reciprocal crosses of WT and α/+ mice. We demonstrate that placental growth and structure were impaired and associated with reduced growth of α/+ fetuses. Despite its defective development, the α/+ placenta adapted functionally to increase the supply of maternal glucose and amino acid to the fetus. The specific nature of these changes, however, depended on whether the mother was α/+ or WT and related to alterations in endocrine and metabolic profile induced by maternal p110α deficiency. Our findings thus show that the maternal genotype and environment programs placental growth and function and identify the placenta as critical in integrating both intrinsic and extrinsic signals governing materno-fetal resource allocation.