Ethanol consumption during gestation promotes placental alterations in IGF-1 deficient mice

Background: During pregnancy, the placenta is an extremely important organ as it secretes its own hormones, e.g. insulin-like growth factor 1 (IGF-1), to ensure proper intrauterine fetal growth and development. Ethanol, an addictive and widely used drug, has numerous adverse effects during pregnancy, including fetal growth restriction (FGR). To date, the molecular mechanisms by which ethanol triggers its toxic effects during pregnancy, particularly in the placenta, are not entirely known. For this reason, a murine model of partial IGF-1 deficiency was used to determine ethanol alterations in placental morphology and AAH expression. Methods: Heterozygous (HZ, Igf1+/-) female mice were given 10% ethanol during 14 days as an acclimation period and throughout pregnancy. HZ female mice given water were used as controls. At gestational day 19, pregnant dams were sacrificed, placentas were collected and genotyped for subsequent studies. Results: IGF-1 deficiency and ethanol consumption during pregnancy altered placental morphology, and decreased placental efficiency and aspartyl/asparaginyl β-hydroxylase (AAH) expression in placentas from all genotypes. No differences were found in Igf1, Igf2, Igf1r and Igf2r mRNA expression in placentas from all groups. Conclusions: IGF-1 deficiency and ethanol consumption throughout gestation altered placental development, suggesting the crucial role of IGF-1 in the establishment of an adequate intrauterine environment that allows fetal growth. However, more studies are needed to study the precise mechanism to stablish the relation between both insults.

Gestational Cd Exposure in the CD-1 Mouse Sex-Specifically Disrupts Essential Metal Ion Homeostasis

In CD-1 mice, gestational-only exposure to cadmium (Cd) causes female-specific hepatic insulin resistance, metabolic disruption, and obesity. To evaluate whether sex differences in cadmium uptake and changes in essential metal concentrations contribute to metabolic outcomes, placental and liver cadmium and essential metal concentrations were quantified in male and female offspring perinatally exposed to 500 ppb CdCl2. Exposure resulted in increased maternal liver Cd+2 concentrations (364 microgram/kg) similar to concentrations found in non-occupationally exposed human liver. At gestational day (GD) 18, placental cadmium and manganese concentrations were significantly increased in exposed males and females, and zinc was significantly decreased in females. Placental efficiency was significantly decreased in GD18 exposed males. Increases in hepatic Cd concentrations and a transient prenatal increase in zinc were observed in exposed female liver. Fetal and adult liver iron concentrations were decreased in both sexes, and decreases in hepatic zinc, iron, and manganese were observed in exposed females. Analysis of GD18 placental and liver metallothionein mRNA expression revealed significant Cd-induced upregulation of placental metallothionein in both sexes, and a significant decrease in fetal hepatic metallothionein in exposed females. In placenta, expression of metal ion transporters responsible for metal ion uptake was increased in exposed females. In liver of exposed adult female offspring, expression of the divalent cation importer (Slc39a14/Zip14) decreased, whereas expression of the primary exporter (Slc30a10) increased. These findings demonstrate that Cd can preferentially cross the female placenta, accumulate in the liver, and cause lifelong dysregulation of metal ion concentrations associated with metabolic disruption.

TRIB3-Regulated Akt Signal Pathway Affects Trophoblast Invasion in the Development of Preeclampsia

Objective The aim of the study is to explore the mechanism of tribbles pseudokinase 3 (TRIB3)-regulated Akt pathway in the development of preeclampsia (PE). Methods TRIB3 expression in the placenta of PE patient was determined by quantitative reverse transcriptase polymerase chain reaction and western blotting. Then HTR-8/SVneo or JEG-3 cells were transfected and divided into Mock, Control siRNA, TRIB3 siRNA-1, and TRIB3 siRNA-2 groups. Cell proliferation, invasion, and migration were determined by MTT assay, Transwell assay, and wound healing test, while the expression of TRIB3 and Akt pathway was measured by western blotting. PE rats were treated with TRIB3 siRNA, and blood pressure, 24-hour urinary protein, as well as serum levels of sFlt-1 and vascular endothelial growth factor (VEGF) were measured. Results The placenta of PE patients presented with increased TRIB3 expression. In comparison with Mock group, the proliferation, invasion, and migration of HTR-8/SVneo and JEG-3 cells in TRIB3 siRNA-1 group and TRIB3 siRNA-2 group increased, with decreased TRIB3 expression but enhanced expression of p-Akt/Akt, MMP-2, and MMP-9. Rats in PE group showed increases in mean arterial pressure, SBP, 24-hour urinary protein, and serum sFlt-1 levels, but decreases in serum VEGF levels, fetal weight, and placental efficiency. Moreover, TRIB3 expression was upregulated, while p-Akt/Akt was downregulated in the placenta of rats in PE group. However, indicators above were significantly improved in rats treated with TRIB3 siRNA. Conclusion TRIB3 was upregulated in the PE placenta, while silencing TRIB3 activated the Akt signaling pathway to promote the invasion and migration of trophoblast both in vitro and in vivo and ameliorated the development of PE symptoms in the PE rat model. Key Points

Abstract 03: Ablation Of Endothelial Dysfunction Improves Blood Pressure And Fetal Growth Restriction In A Mouse Model Of Preeclampsia-like Hyperleptinemia

Placental ischemia, an initiating event of preeclampsia (PE), increases plasma leptin levels. We recently developed a model of midgestation (gestation day (GD)11-18) leptin infusion mimicking the midgestation rise in leptin levels of PE patients. Our previous work demonstrates that deletion of endothelial mineralocorticoid receptors (ECMR) improves markers of vascular dysfunction in leptin-infused female mice. We hypothesized vascular function improvement with ECMR deletion ablates hypertension and fetal growth restriction in pregnant leptin-infused mice. Pregnant ECMR +/+ (WT) and ECMR -/- (KO) mice were infused with vehicle or leptin by osmotic pump (lep, 0.9mg/kg/day, s.c.) on GD11-18 while implanted with radiotelemeters for conscious blood pressure (BP) measurement and wire myography of thoracic aorta and 2 nd order mesenteric arteries at GD18 (*=P<0.05). Leptin infusion did not decrease maternal weight in any groups. Leptin decreased pup weight (0.86±0.04g WT vs 0.52±0.11 WT+lep*) and placental efficiency (pup/placenta ratio) (9.7±0.7 WT vs 7.9±0.6 WT+lep*) in WT pregnant mice. ECMR deletion prevented leptin-mediated decreases in pup weight (0.91±0.06g KO vs 1.0±0.07 KO+lep) and placental efficiency (9.6±0.5 KO vs 9.4±1.2 KO+lep). Mean arterial pressure (BP) increased in leptin-infused WT (102±3mmHg WT vs 120±12 WT+lep*), but not KO (107±2 KO vs 106±8 KO+lep), mice from GD11-18. Leptin infusion reduced acetylcholine-mediated relaxation in both aorta and mesenteric arteries of WT* and constriction to KCl in mesenteric arteries in WT*, but not KO, pregnant mice (2-way ANOVA, repeated measures). Leptin increased plasma endothelin-1 (ET-1, 1.1±0.3 pg/ml WT vs 4.4±1.8 WT+lep*), placental mRNA expression of prepro-ET-1 (1.9±0.3-fold change from WT*) and ET-1 converting enzyme-1 (1.6±0.3-fold change from WT*) in pregnant WT mice. Leptin infusion also increased adrenal aldosterone-synthase protein (1.4±0.4 WT ratio/β actin vs 3.2±0.3 WT+lep*) and angiotensin II type 1 receptor b (3.5±0.8-fold change from WT*) mRNA in pregnant mice. Collectively, these data indicate that leptin infusion induces hypertension and fetal growth restriction in pregnant mice due to vascular dysfunction and increased ECMR activation in pregnant mice.

Late Gestation Maternal Feed Restriction Decreases Microbial Diversity of the Placenta while Mineral Supplementation Improves Richness of the Fetal Gut Microbiome in Cattle

Feed intake restriction impacts both humans and ruminants in late gestation, although it is unknown whether this adverse maternal environment influences the microbiome of the reproductive tract, and through it, the colonization of the fetal gut. A 2 × 2 factorial design including a 70% feed intake restriction (feed restricted ‘FR’ or control diets ‘CON’) and mineral supplementation (unsupplemented ‘S−’ or supplemented ‘S+’) was used to analyze these effects in multiparous cows (n = 27). Vaginal swabs were obtained 60, 30, and 10 days prior to the estimated calving date, along with neonatal rumen fluid and meconium. Placental tissues and efficiency measurements were collected. Microbial DNA was extracted for 16S sequencing of the V4 region. Feed restriction decreased the diversity of the placental microbiome, but not the vagina, while mineral supplementation had little impact on these microbial communities. Mineral supplementation did improve the richness and diversity of the fetal gut microbiomes in relation to reproductive microbes. These differences within the placental microbiome may influence individual health and performance. Adequate maternal nutrition and supplementation yielded the greatest placental efficiency, which may aid in the establishment of a healthy placental microbiome and fetal microbial colonization.

Maternal underweight and obesity are associated with placental pathologies in human pregnancy

Introduction: Maternal underweight and obesity are prevalent conditions, associated with chronic, low-grade inflammation, poor fetal development, and long-term adverse outcomes for the child. The placenta senses and adapts to the pregnancy environment in an effort to support optimal fetal development. However, the mechanisms driving these adaptations, and the resulting placental phenotypes, are poorly understood. We hypothesised that maternal underweight and obesity would be associated with increased prevalence of placental pathologies in term and preterm pregnancies. Methods: Data from 12,154 pregnancies were obtained from the Collaborative Perinatal Project, a prospective cohort study conducted from 1959 to 1974. Macro and microscopic placental pathologies were analysed across maternal prepregnancy body mass index (BMI) to assess differences in the presence of pathologies among underweight, overweight, and obese BMI groups compared to normal weight reference BMI at term and preterm. Placental pathologies were also assessed across fetal sex. Results: Pregnancies complicated by obesity had placentae with increased fetal inflammation at preterm and increased maternal inflammation at term. In term pregnancies, increasing maternal BMI associated with increased maternal vascular malperfusion (MVM), odds of an appropriate mature placenta for gestational age, and placental weight, and decreased placental efficiency. Male placentae, independent of maternal BMI, had increased inflammation, MVM, and placental efficiency than female placentae, particularly at term. Discussion: Maternal underweight and obesity are not inert conditions for the placenta, and the histomorphological changes driven by suboptimal maternal BMI may serve as indicators of adversities experienced in utero and potential predictors of future health trajectories.

35 Effect of Late Gestational Heat Stress on Placental Characteristics in Dairy Cattle

To determine the effects of late gestation heat stress on placental development, dairy cows were exposed to heat stress (HT, shade) or cooled (CL, shade, fans and soakers) during the final 46 d pre-calving on the University of Florida dairy facility (temperature-humidity index; THI &gt;68). We hypothesize heat stress (or lack of heat abatement) will reduce placental efficiency and in turn increase placental weight, surface area, and volume. At expulsion all placentae were collected and total placental weight was determined as well as individual cotyledonary weights, surface areas, and volume. In addition, the total number of total cotyledons was recorded and cotyledonary color and placental growth abnormalities (i.e. teratomas) were recorded and photographed. All data were analyzed using PROC MIXED in SAS. In addition, associations between parameters were determined by calculating Pearson Correlation Coefficients using SAS. Placentae from HT cows had a higher total placental weight, higher non-vascular membrane weight, higher total cotyledonary weight, higher total cotyledonary volume, and a higher incidence of teratomas than those from CL cows (P &lt; 0.05). HT cows also had placentae with a significantly greater average cotyledonary weight and volume (P &lt; 0.05). HT cows tended to have a greater incidence of color abnormalities in the placenta (P &lt; 0.075). In addition, HT cows had significantly lighter calves at birth (P &lt; 0.05). These data demonstrate that heat stress (or lack of heat abatement) impacts placental growth during the final stages of gestation, resulting in heavier placentae, an increase in cotyledonary weight and volume, but not an increase in the total number of cotyledons or total cotyledonary surface area. These placental alterations ultimately resulted in lighter calves at birth.

Maternal Heat Stress Alters Expression of Genes Associated with Nutrient Transport Activity and Metabolism in Female Placentae from Mid-Gestating Pigs

Placental insufficiency is a known consequence of maternal heat stress during gestation in farm animals. The molecular regulation of placentae during the stress response is little known in pigs. This study aims to identify differential gene expression in pig placentae caused by maternal heat exposure during early to mid-gestation. RNA sequencing (RNA-seq) was performed on female placental samples from pregnant pigs exposed to thermoneutral control (CON; constant 20 °C; n = 5) or cyclic heat stress (HS; cyclic 28 to 33 °C; n = 5) conditions between d40 and d60 of gestation. On d60 of gestation, placental efficiency (fetal/placental weight) was decreased (p = 0.023) by maternal HS. A total of 169 genes were differentially expressed (FDR ≤ 0.1) between CON and HS placentae of female fetuses, of which 35 genes were upregulated and 134 genes were downregulated by maternal HS. The current data revealed transport activity (FDR = 0.027), glycoprotein biosynthetic process (FDR = 0.044), and carbohydrate metabolic process (FDR = 0.049) among the terms enriched by the downregulated genes (HS vs. CON). In addition, solute carrier (SLC)-mediated transmembrane transport (FDR = 0.008) and glycosaminoglycan biosynthesis (FDR = 0.027), which modulates placental stroma synthesis, were identified among the pathways enriched by the downregulated genes. These findings provide evidence that heat-stress induced placental inefficiency may be underpinned by altered expression of genes associated with placental nutrient transport capacity and metabolism. A further understanding of the molecular mechanism contributes to the identification of placental gene signatures of summer infertility in pigs.