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Ovine uterine space restriction alters placental transferrin receptor and fetal iron status during late pregnancy.

ABSTRACT: Fetal growth restriction is reported to be associated with impaired placental iron transport. Transferrin receptor (TfR) is a major placental iron transporter in humans but has not been studied in sheep. TfR is regulated by both iron and nitric oxide (NO), the molecule produced by endothelial nitric oxide synthase (eNOS). We hypothesized that limited placental development downregulates both placental TfR and eNOS expression, thereby lowering fetal tissue iron.An ovine surgical uterine space restriction (USR) model, combined with multifetal gestation, tested the extremes of uterine and placental adaptation. Blood, tissues, and placentomes from non-space restricted (NSR) singletons were compared with USR fetuses at gestational day (GD) 120 or 130.When expressed proportionate to fetal weight, liver iron content did not differ, whereas renal iron was higher in USR vs. NSR fetuses. Renal TfR protein expression did not differ, but placental TfR expression was lower in USR fetuses at GD130. Placental levels of TfR correlated to eNOS. TfR was localized throughout the placentome, including the hemophagous zone, implicating a role for TfR in ovine placental iron transport.Fetal iron was regulated in an organ-specific manner. In USR fetuses, NO-mediated placental adaptations may prevent the normal upregulation of placental TfR at GD130.

SUBMITTER: Sun MY

PROVIDER: S-EPMC3678369 | biostudies-literature | 2013 Mar

REPOSITORIES: biostudies-literature

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Ovine uterine space restriction alters placental transferrin receptor and fetal iron status during late pregnancy.

Sun Mary Y MY Habeck Jason M JM Meyer Katie M KM Koch Jill M JM Ramadoss Jayanth J Blohowiak Sharon E SE Magness Ronald R RR Kling Pamela J PJ

Pediatric research 20121130 3

<h4>Background</h4>Fetal growth restriction is reported to be associated with impaired placental iron transport. Transferrin receptor (TfR) is a major placental iron transporter in humans but has not been studied in sheep. TfR is regulated by both iron and nitric oxide (NO), the molecule produced by endothelial nitric oxide synthase (eNOS). We hypothesized that limited placental development downregulates both placental TfR and eNOS expression, thereby lowering fetal tissue iron.<h4>Methods</h4>A ...[more]

PMID: 23202722

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Project description:Fetal growth restriction (FGR) occurs when the fetus does not reach its genetically programmed intrauterine potential for growth and affects ~5‑10% of pregnancies. This condition is one of the leading causes of perinatal mortality and morbidity associated with obstetric and neonatal complications. Placental dysfunction in FGR causes an impairment in the transfer of nutrients and oxygen from the mother to the developing fetus. Maternal adaptations to placental insufficiency may also play a role in the pathophysiology of FGR. The present study aimed to compare the proteome of the placentas of 18 women with the physiological course of pregnancy and eutrophic fetus [estimated fetal weight (EFW) >10th percentile; control group] and 18 women with late FGR (EFW <10th percentile) diagnosed after 32 weeks of pregnancy, according to the Delphi consensus (study group). The U. Mann‑Whitney test was used to compare two independent groups. The R. Spearman correlation coefficient significance test was used to assess the existence of a relationship between the analyzed measurable parameters. P<0.05 was considered to indicate a statistically significant difference. The tests showed the presence of 356 different proteins which were responsible for the regulation of gene transcription control, inhibiting the activity of proteolytic enzymes, regulation of trophoblast proliferation and angiogenesis and inflammatory response. In the FGR placental proteome, other detected proteins were mostly involved in response to oxidative stress, cellular oxidation and detoxication, apoptosis, hemostatic and catabolic processes, energy transduction protein interactions, cell proliferation, differentiation and intracellular signaling. The present study used chromatographic mass‑spectrometry to compare the placental proteome profiles in pregnancies complicated by late‑onset FGR and normal pregnancy. Comparative analysis of proteomes from normal and FGR placentas showed significant differences. Further research is needed to clarify maternal and fetal adaptations to FGR.

Project description:BackgroundExposure to bisphenol A (BPA), an environmental pollutant known for its endocrine-disrupting properties, during gestation has been reported to increase the risk of fetal growth restriction (FGR) in an ovine model of pregnancy. We hypothesized that the FGR results from the BPA-induced insufficiency and barrier dysfunction of the placenta, oxidative stress, inflammatory responses, autophagy and endoplasmic reticulum stress (ERS). However, precise mechanisms underlying the BPA-induced placental dysfunction, and subsequently, FGR, as well as the potential involvement of placental ERS in these complications, remain to be investigated.MethodsIn vivo experiment, 16 twin-pregnant (from d 40 to 130 of gestation) Hu ewes were randomly distributed into two groups (8 ewes each). One group served as a control and received corn oil once a day, whereas the other group received BPA (5 mg/kg/d as a subcutaneous injection). In vitro study, ovine trophoblast cells (OTCs) were exposed to 4 treatments, 6 replicates each. The OTCs were treated with 400 μmol/L BPA, 400 μmol/L BPA + 0.5 μg/mL tunicamycin (Tm; ERS activator), 400 μmol/L BPA + 1 μmol/L 4-phenyl butyric acid (4-PBA; ERS antagonist) and DMEM/F12 complete medium (control), for 24 h.ResultsIn vivo experiments, pregnant Hu ewes receiving the BPA from 40 to 130 days of pregnancy experienced a decrease in placental efficiency, progesterone (P4) level and fetal weight, and an increase in placental estrogen (E2) level, together with barrier dysfunctions, OS, inflammatory responses, autophagy and ERS in type A cotyledons. In vitro experiment, the OTCs exposed to BPA for 24 h showed an increase in the E2 level and related protein and gene expressions of autophagy, ERS, pro-apoptosis and inflammatory response, and a decrease in the P4 level and the related protein and gene expressions of antioxidant, anti-apoptosis and barrier function. Moreover, treating the OTCs with Tm aggravated BPA-induced dysfunction of barrier and endocrine (the increased E2 level and decreased P4 level), OS, inflammatory responses, autophagy, and ERS. However, treating the OTCs with 4-PBA reversed the counteracted effects of Tm mentioned above.ConclusionsIn general, the results reveal that BPA exposure can cause ERS in the ovine placenta and OTCs, and ERS induction might aggravate BPA-induced dysfunction of the placental barrier and endocrine, OS, inflammatory responses, and autophagy. These data offer novel mechanistic insights into whether ERS is involved in BPA-mediated placental dysfunction and fetal development.

Project description:BackgroundAdministration of progesterone (P4) to ewes during the first 9 to 12 days of pregnancy accelerates blastocyst development by day 12 of pregnancy, likely due to P4-induced up-regulation of key genes in uterine epithelia responsible for secretion and transport of components of histotroph into the uterine lumen. This study determined if acceleration of blastocyst development induced by exogenous P4 during the pre-implantation period affects fetal-placental development on day 125 of pregnancy. Suffolk ewes (n = 35) were mated to fertile rams and assigned randomly to receive daily intramuscular injections of either corn oil vehicle (CO, n = 18) or 25 mg progesterone in CO (P4, n = 17) for the first 8 days of pregnancy. All ewes were hysterectomized on day 125 of pregnancy and: 1) fetal and placental weights and measurements were recorded; 2) endometrial and placental tissues were analyzed for the expression of candidate mRNAs involved in nutrient transport and arginine metabolism; and 3) maternal plasma, fetal plasma, allantoic fluid, and amniotic fluid were analyzed for amino acids, agmatine, polyamines, glucose, and fructose.ResultsTreatment of ewes with exogenous P4 did not alter fetal or placental growth, but increased amounts of aspartate and arginine in allantoic fluid and amniotic fluid, respectively. Ewes that received exogenous P4 had greater expression of mRNAs for SLC7A1, SLC7A2, SLC2A1, AGMAT, and ODC1 in endometria, as well as SLC1A4, SLC2A5, SLC2A8 and ODC1 in placentomes. In addition, AZIN2 protein was immunolocalized to uterine luminal and glandular epithelia in P4-treated ewes, whereas AZIN2 localized only to uterine luminal epithelia in CO-treated ewes.ConclusionsThis study revealed that exogenous P4 administered in early pregnancy influenced expression of selected genes for nutrient transporters and the expression of a protein involved in polyamine synthesis on day 125 of pregnancy, suggesting a 'programming' effect of P4 on gene expression that affected the composition of nutrients in fetal-placental fluids.

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Ovine uterine space restriction alters placental transferrin receptor and fetal iron status during late pregnancy.

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Ovine uterine space restriction alters placental transferrin receptor and fetal iron status during late pregnancy.

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