Placental phenotypes of intrauterine growth

The tyrosine phosphatase SHP-1 negatively regulates cytotrophoblast proliferation in first-trimester human placenta by modulating EGFR activation

Insulin-like growth factors (IGFs) influence placental cell (cytotrophoblast) kinetics. We recently reported that the protein tyrosine phosphatase (PTP) SHP-2 positively regulates IGF actions in the placenta. In other systems, the closely related PTP, SHP-1, functions as a negative regulator of signaling events but its role in the placenta is still unknown. We examined the hypothesis that SHP-1 negatively regulates IGF actions in the human placenta. Immunohistochemical (IHC) analysis demonstrated that SHP-1 is abundant in cytotrophoblast. SHP-1 expression was decreased in first-trimester placental explants using siRNA; knockdown did not alter IGF-induced proliferation but it significantly enhanced proliferation in serum-free conditions, revealing that placental growth is endogenously regulated. Candidate regulators were determined by using antibody arrays, Western blotting, and IHC to examine the activation status of multiple receptor tyrosine kinases (RTKs) in SHP-1-depleted explants; amongst the alterations observed was enhanced activation of EGFR, suggesting that SHP-1 may interact with EGFR to inhibit proliferation. The EGFR tyrosine kinase inhibitor PD153035 reversed the elevated proliferation seen in the absence of SHP-1. This study demonstrates a role for SHP-1 in human trophoblast turnover and establishes SHP-1 as a negative regulator of EGFR activation. Targeting placental SHP-1 expression may provide therapeutic benefits in common pregnancy conditions with abnormal trophoblast proliferation.

Crossing mice deficient in eNOS with placental-specific Igf2 knockout mice: a new model of fetal growth restriction

We tested the hypothesis that crossing two mouse models of fetal growth restriction (FGR) of differing phenotype would induce more severe FGR than either model alone. Female endothelial nitric oxide synthase knockout mice (eNOS(-/-)) were mated with placental-specific Igf2 knockout males (P0). Resultant fetuses were no more growth restricted than those with P0 deletion alone. However, P0 deletion attenuated the reduced placental system A amino acid transporter activity previously observed in eNOS(-/-) mice. Manipulating maternal and fetal genotypes provides a means to compare maternal and fetal regulation of fetal growth.

Lack of activation of peripheral blood dendritic cells in human pregnancies complicated by intrauterine growth restriction

INTRODUCTION

The state of activation of dendritic cells (DCs) at the feto-maternal interface critically contributes to optimal decidual immune responses needed to support fetal-placental development. We recently demonstrated that during healthy pregnancy also peripheral blood DCs (PBDCs), which are easily accessible, are activated as well. In this study, to investigate a possible involvement of DCs in intrauterine growth restriction (IUGR), we evaluated whether PBDCs in pregnancy complicated by IUGR may be altered compared with PBDCs in healthy pregnancy.

METHODS

PBDCs from 12 pregnant women with primary IUGR, 21 healthy pregnant and 19 nonpregnant women were analyzed by flow cytometric analysis of whole-blood samples collected at a single time point.

RESULTS

The number of plasmacytoid PBDCs was significantly reduced in women with IUGR pregnancy. Myeloid and plasmacytoid PBDCs in IUGR lacked the state of activation (assessed as CD80, CD86, CD40 expression) and the shift to a proinflammatory pattern of cytokine production occurring during healthy pregnancy.

DISCUSSION

To our knowledge, this is the first study investigating the state of PBDC activation in IUGR pregnancy. Our results are in accordance with a previous study reporting a lower expression of activation and maturation markers by decidual DCs in IUGR placentas.

CONCLUSIONS

The reduced activation of PBDCs in IUGR pregnancy may possibly reflect a reduced activation of decidual DCs. If confirmed at the feto-maternal interface, the alterations of DCs described in IUGR pregnancy have the potential to negatively impact on vascular development during gestation. These observations may therefore broaden our understanding of IUGR pathogenesis.

Mammalian target of rapamycin signalling modulates amino acid uptake by regulating transporter cell surface abundance in primary human trophoblast cells

Abnormal fetal growth increases the risk for perinatal complications and predisposes for the development of obesity, diabetes and cardiovascular disease later in life. Emerging evidence suggests that changes in placental amino acid transport directly contribute to altered fetal growth. However, the molecular mechanisms regulating placental amino acid transport are largely unknown. Here we combined small interfering (si) RNA-mediated silencing approaches with protein expression/localization and functional studies in cultured primary human trophoblast cells to test the hypothesis that mammalian target of rapamycin complex 1 (mTORC1) and 2 (mTORC2) regulate amino acid transporters by post-translational mechanisms. Silencing raptor (inhibits mTORC1) or rictor (inhibits mTORC2) markedly decreased basal System A and System L amino acid transport activity but had no effect on growth factor-stimulated amino acid uptake. Simultaneous inhibition of mTORC1 and 2 completely inhibited both basal and growth factor-stimulated amino acid transport activity. In contrast, mTOR inhibition had no effect on serotonin transport. mTORC1 or mTORC2 silencing markedly decreased the plasma membrane expression of specific System A (SNAT2, SLC38A2) and System L (LAT1, SLC7A5) transporter isoforms without affecting global protein expression. In conclusion, mTORC1 and mTORC2 regulate human trophoblast amino acid transporters by modulating the cell surface abundance of specific transporter isoforms. This is the first report showing regulation of amino acid transport by mTORC2. Because placental mTOR activity and amino acid transport are decreased in human intrauterine growth restriction our data are consistent with the possibility that dysregulation of placental mTOR plays an important role in the development of abnormal fetal growth.

Toward a nonhuman primate model of fetal programming: phenotypic plasticity of the common marmoset fetoplacental complex

Nonhuman primates offer unique opportunities as animal models in the study of developmental programming and the role of the placenta in developmental processes. All primates share fundamental similarities in life history and reproductive biology. Thus, insights gleaned from studies of nonhuman primates have a higher degree of biological salience to human biology than do studies of rodents or agricultural animals. The common marmoset monkey is a small-bodied primate from South America that produces litters of dizygotic fetuses that share a single placental mass. This natural variation allows us to model different intrauterine conditions and associated fetoplacental phenotypes. The marmoset placenta is phenotypically plastic according to litter size. Triplet litters are characterized by low individual fetal weights and significantly more efficient placentas and attendant alterations to the microscopic architecture and endocrine function, thus modeling a nutrient restricted intrauterine environment. Consistent with this model, triplet neonates experience a higher risk of perinatal mortality and an increased likelihood of elevated adult weight. Recent evidence has shown that the intrauterine experience of females has an impact on their own pregnancy outcomes in adulthood: triplet females experience significantly greater pregnancy loss than do twin females. The marmoset monkey thus represents a potential powerful nonhuman primate model of multiple pregnancies, restrictive prenatal experiences, and differential reproductive outcomes in adulthood, which may have important implications for studying the impact of in vitro fertilization on adult reproductive health. It is still too early to determine exactly what developmental pathways lead to this disparity or what specific role the placenta plays; future work on this front will be critical to establish the marmoset as an important model of fetal programming of reproductive function in adulthood and across generations.

Placental regulation of maternal-fetal interactions and brain development

A variety prenatal insults are associated with the incidence of neurodevelopmental disorders such as schizophrenia, autism and cerebral palsy. While the precise mechanisms underlying how transient gestational challenges can lead to later life dysfunctions are largely unknown, the placenta is likely to play a key role. The literal interface between maternal and fetal cells resides in the placenta, and disruptions to the maternal or intrauterine environment are necessarily conveyed to the developing embryo via the placenta. Placental cells bear the responsibility of promoting maternal tolerance of the semiallogeneic fetus and regulating selective permeability of nutrients, gases, and antibodies, while still providing physiological protection of the embryo from adversity. The placenta's critical role in modulating immune protection and the availability of nutrients and endocrine factors to the offspring implicates its involvement in autoimmunity, growth restriction and hypoxia, all factors associated with the development of neurological complications. In this review, we summarize primary maternal-fetal interactions that occur in the placenta and describe pathways by which maternal insults can impair these processes and disrupt fetal brain development. We also review emerging evidence for placental dysfunction in the prenatal programming of neurodevelopmental disorders.

Novel use of proton magnetic resonance spectroscopy (1HMRS) to non-invasively assess placental metabolism

Background

Placental insufficiency is a major cause of antepartum stillbirth and fetal growth restriction (FGR). In affected pregnancies, delivery is expedited when the risks of ongoing pregnancy outweigh those of prematurity. Current tests are unable to assess placental function and determine optimal timing for delivery. An accurate, non-invasive test that clearly defines the failing placenta would address a major unmet clinical need. Proton magnetic resonance spectroscopy (¹H MRS) can be used to assess the metabolic profile of tissue in-vivo. In FGR pregnancies, a reduction in N-acetylaspartate (NAA)/choline ratio and detection of lactate methyl are emerging as biomarkers of impaired neuronal metabolism and fetal hypoxia, respectively. However, fetal brain hypoxia is a late and sometimes fatal event in placental compromise, limiting clinical utility of brain ¹H MRS to prevent stillbirth. We hypothesised that abnormal placental ¹H MRS may be an earlier biomarker of intrauterine hypoxia, affording the opportunity to optimise timing of delivery in at-risk fetuses.

Methods and Findings

We recruited three women with severe placental insufficiency/FGR and three matched controls. Using a 3T MR system and a combination of phased-array coils, a 20×20×40 mm¹H MRS voxel was selected along the ‘long-axis’ of the placenta with saturation bands placed around the voxel to prevent contaminant signals. A significant choline peak (choline/lipid ratio 1.35–1.79) was detected in all healthy placentae. In contrast, in pregnancies complicated by FGR, the choline/lipid ratio was ≤0.02 in all placentae, despite preservation of the lipid peak (p<0.001).

Conclusions

This novel proof-of-concept study suggests that in severe placental insufficiency/FGR, the observed 60-fold reduction in the choline/lipid ratio by ¹H MRS may represent an early biomarker of critical placental insufficiency. Further studies will determine performance of this test and the potential role of 1H-MRS in the in-vivo assessment of placental function to inform timing of delivery.

Placental size is associated with mental health in children and adolescents

BACKGROUND

The role of the placenta in fetal programming has been recognized as a highly significant, yet often neglected area of study. We investigated placental size in relation to psychopathology, in particular attention deficit hyperactivity disorder (ADHD) symptoms, in children at 8 years of age, and later as adolescents at 16 years.

METHODOLOGY/PRINCIPAL FINDINGS

Prospective data were obtained from The Northern Finland Birth Cohort (NFBC) 1986. Placental weight, surface area and birth weight were measured according to standard procedures, within 30 minutes after birth. ADHD symptoms, probable psychiatric disturbance, antisocial disorder and neurotic disorder were assessed at 8 years (n = 8101), and ADHD symptoms were assessed again at 16 years (n = 6607), by teachers and parents respectively. We used logistic regression analyses to investigate the association between placental size and mental health outcomes, and controlled for gestational age, birth weight, socio-demographic factors and medical factors, during gestation. There were significant positive associations between placental size (weight, surface area and placental-to-birth-weight ratio) and mental health problems in boys at 8 and 16 years of age. Increased placental weight was linked with overall probable psychiatric disturbance (at 8 y, OR= 1.14 [95% CI= 1.04-1.25]), antisocial behavior (at 8 y, OR = 1.14 [95% CI= 1.03-1.27]) and ADHD symptoms (inattention-hyperactivity at 16 y, OR= 1.19 [95% CI = 1.02-1.38]). No significant associations were detected among girls.

CONCLUSIONS/SIGNIFICANCE

Compensatory placental growth may occur in response to prenatal insults. Such overgrowth may affect fetal development, including brain development, and ultimately contribute to psychopathology.

Effect of the anti-oxidant tempol on fetal growth in a mouse model of fetal growth restriction

Fetal growth restriction (FGR) greatly increases the risk of perinatal morbidity and mortality and is associated with increased uterine artery resistance and levels of oxidative stress. There are currently no available treatments for this condition. The hypothesis that the antioxidant 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (Tempol) would improve uterine artery function and rescue fetal growth was tested in a mouse model of FGR, using the endothelial nitric oxide synthase knockout mouse (Nos3(-/-)). Pregnant Nos3(-/-) and control C57BL/6J mice were treated with the superoxide dismutase-mimetic Tempol (1 mmol/L) or vehicle from Gestational Day 12.5 to 18.5. Tempol treatment significantly increased pup weight (P < 0.05) and crown-rump length (P < 0.01) in C57BL/6J and Nos3(-/-) mice. Uterine artery resistance was increased in Nos3(-/-) mice (P < 0.05); Tempol significantly increased end diastolic velocity in Nos3(-/-) mice (P < 0.05). Superoxide production in uterine arteries did not differ between C57BL/6J and Nos3(-/-) mice but was significantly increased in placentas from Nos3(-/-) mice (P < 0.05). This was not reduced by Tempol treatment. Placental System A activity was reduced in Nos3(-/-) mice (P < 0.01); this was not improved by treatment with Tempol. Treatment of Nos3(-/-) mice with Tempol, however, was associated with reduced vascular density in the placental bed (P < 0.05). This study demonstrated that treatment with the antioxidant Tempol is able to improve fetal growth in a mouse model of FGR. This was associated with an increase in uterine artery blood flow velocity but not an improvement in uterine artery function or placental System A activity.

eNOS knockout mouse as a model of fetal growth restriction with an impaired uterine artery function and placental transport phenotype

Fetal growth restriction (FGR) is the inability of a fetus to reach its genetically predetermined growth potential. In the absence of a genetic anomaly or maternal undernutrition, FGR is attributable to "placental insufficiency": inappropriate maternal/fetal blood flow, reduced nutrient transport or morphological abnormalities of the placenta (e.g., altered barrier thickness). It is not known whether these diverse factors act singly, or in combination, having additive effects that may lead to greater FGR severity. We suggest that multiplicity of such dysfunction might underlie the diverse FGR phenotypes seen in humans. Pregnant endothelial nitric oxide synthase knockout (eNOS(-/-)) dams exhibit dysregulated vascular adaptations to pregnancy, and eNOS(-/-) fetuses of such dams display FGR. We investigated the hypothesis that both altered vascular function and placental nutrient transport contribute to the FGR phenotype. eNOS(-/-) dams were hypertensive prior to and during pregnancy and at embryonic day (E) 18.5 were proteinuric. Isolated uterine artery constriction was significantly increased, and endothelium-dependent relaxation significantly reduced, compared with wild-type (WT) mice. eNOS(-/-) fetal weight and abdominal circumference were significantly reduced compared with WT. Unidirectional maternofetal (14)C-methylaminoisobutyric acid (MeAIB) clearance and sodium-dependent (14)C-MeAIB uptake into mouse placental vesicles were both significantly lower in eNOS(-/-) fetuses, indicating diminished placental nutrient transport. eNOS(-/-) mouse placentas demonstrated increased hypoxia at E17.5, with elevated superoxide compared with WT. We propose that aberrant uterine artery reactivity in eNOS(-/-) mice promotes placental hypoxia with free radical formation, reducing placental nutrient transport capacity and fetal growth. We further postulate that this mouse model demonstrates "uteroplacental hypoxia," providing a new framework for understanding the etiology of FGR in human pregnancy.

Exploring the potential of low doses carbon monoxide as therapy in pregnancy complications

Heme Oxygenase-1 (HO-1) has been shown to play a pivotal role in pregnancy outcome and its ablation leads to abnormal placentation, intrauterine fetal growth restriction (IUGR) and subsequent intrauterine fetal death. Carbon monoxide (CO) has been found to mimic the protective effects of HO-1 activity, rescuing HO-1-deficient fetuses. This gasotransmitter arises in biological systems during the oxidative catabolism of heme by HO. Here, we explored the potential of CO in preventing IUGR and established the optimal doses and therapeutic time window in a clinically relevant mouse model. We additionally investigated the pathways activated upon CO application in vivo. We established 50 ppm as the best lowest dose of CO necessary to prevent growth restriction being the optimal time frame during days 3 to 8 of mouse pregnancy. CO lead to higher fetal and placental weights and avoided fetal death without showing any pathologic effects. CO breathing further suppressed inflammatory responses, diminished placenta apoptosis and complement deposition and regulated placental angiogenesis. Our results confirm the protective role of the HO-1/CO axis and point this gas as an emerging therapeutic possibility which is worth to further explore.

Chronic maternal infusion of full-length adiponectin in pregnant mice down-regulates placental amino acid transporter activity and expression and decreases fetal growth

Maternal adiponectin levels are inversely correlated to birth weight, suggesting that maternal adiponectin limits fetal growth. We hypothesized that full-length adiponectin (fADN) infusion in pregnant mice down-regulates placental amino acid transporters and decreases fetal growth. Starting at embryonic day (E) 14.5, fADN (0.62 ± 0.02 μg (g body weight)(−1) day(−1), n = 7) or vehicle (control, n = 9) were infused in pregnant C57/BL6 mice by mini-osmotic pump. At E18.5, dams were killed and placental homogenates and trophoblast plasma membrane (TPM) vesicles were prepared. Infusion of fADN elevated maternal serum fADN by 4-fold and decreased fetal weights by 18%. Adiponectin receptor 2, but not adiponectin receptor 1, was expressed in TPM. fADN infusion decreased TPM System A (–56%, P < 0.001) and System L amino acid transporter activity (–50%, P < 0.03). TPM protein expression of SNAT1, 2 and 4 (System A amino acid transporter isoforms) and LAT1 and LAT2, but not CD98, (System L amino acid transporter isoforms) was down-regulated by fADN infusion. To identify possible mechanisms underlying these changes we determined the phosphorylation of proteins in signalling pathways known to regulate placental amino acid transporters. fADN decreased phosphorylation of insulin receptor substrate-1 (Tyr-608), Akt (Thr-308 and Ser-473), S6 kinase 1 (Thr-389), eukaryotic initiation factor 4E binding protein 1 (Thr-37/46 and Thr-70) and ribosomal protein S6 (Ser-235/236) and increased the phosphorylation of peroxisome proliferator-activated receptor α (PPARα) (Ser-21) in the placenta. These data suggest that maternal adiponectin decreases fetal growth by down-regulation of placental amino acid transporters, which limits fetal nutrient availability. This effect may be mediated by inhibition of insulin/IGF-I and mTOR signalling pathways, which are positive regulators of placental amino acid transporters. We have identified a novel physiological mechanism by which the endocrine functions of maternal adipose tissue influence fetal growth.

Effect of young maternal age and skeletal growth on placental growth and development

OBJECTIVES

Teenagers are susceptible to delivering small-for-gestational-age infants. Previous studies implicate continued skeletal growth as a contributory factor, and impaired placental development was the primary cause of fetal growth restriction in growing adolescent sheep. The aims of this study were to examine the impact of young maternal age and growth on placental development.

STUDY DESIGN

Placentas were collected from 31 teenagers, of which 12 were growing and 17 non-growing based on knee height measurements. An adult control group (n = 12) was included.

MAIN OUTCOME MEASURES

Placental weight and morphometric measurements of villous, syncytiotrophoblast, fibrin and vessel areas, as well as indices of proliferation and apoptosis, were analysed in relation to maternal growth and age.

RESULTS

Growing teenagers had a higher birthweight:placental weight ratio than non-growing teenagers (p < 0.05). Villous area, syncytial area, fibrin content, vascularisation and cell turnover did not differ between growing and non-growing teenagers. There were no differences in placental weight or morphometry between adult and teenage pregnancies. Maternal smoking, a potential confounding factor, did not exert a major influence on the placental parameters examined, except for a stimulatory effect on placental proliferation (p < 0.05) and syncytial knot formation (p < 0.05).

CONCLUSIONS

We were unable to detect any major differences in placental size or composition between growing and non-growing teenagers. Birthweight:placental weight ratio was higher in growing compared to non-growing teenagers. This suggests that maternal growth may affect placental function rather than development, and is consistent with our recent observations that maternal growth was not detrimental to fetal growth.

Magnetic resonance imaging relaxation time measurements of the placenta at 1.5 T

Placental insufficiency is a major cause of fetal growth restriction (FGR) and accumulating evidence indicates several aspects of placental morphology are altered in this condition. MRI provides quantitative indices that may be used in non-invasive assessment of the human placenta, such as relaxation time measurements, T1 and T2. We hypothesised that placental relaxation times relate to alterations in placental tissue morphology and hence may be useful in identifying the changes associated with FGR. We report on the first phase of testing this hypothesis, in a study of women in normal pregnancy.

AIMS

To assess relaxation time measurements in the placenta in normal pregnancy and correlate these with gestational age and stereological analyses of placental morphology following delivery.

METHODS

30 women underwent MRI examination (1.5 T) between 20 and 41 weeks gestation. Placental T1 and T2 measurements were acquired from a mid-depth placental region, co-localised to a structural scan. Fixed, wax-embedded sections of these placentas collected at delivery were stained with hematoxylin/eosin and subjected to stereological analysis.

RESULTS

Placental T1 and T2 show a significant negative correlation with gestation, (Pearson correlation p=0.01, 0.03 respectively). 17 placentas were analysed stereologically. In the group as a whole there was no significant correlation between T1 and T2 and morphological features. However, in a subset of 7 pregnancies scanned within a week of delivery, a significant positive correlation was observed between the fibrin volume density and the ratio of fibrin: villous volume densities and T2 (Spearman correlation p=0.02, 0.03 respectively).

DISCUSSION

The correlations between placental T1 and T2 and gestation show that these variables are clearly influenced by changes in placental structure. Fibrin might be a key component but further work is needed to fully elucidate the major structural influences on placental T1 and T2.

System A activity and vascular function in the placental-specific Igf2 knockout mouse

OBJECTIVES

Deletion of the placental-specific P0 transcript of the insulin-like growth factor gene (Igf2) reduces placental growth from early pregnancy onwards. In Igf2 P0 knockout fetuses (P0), maternofetal flux of (14)C-methylaminoisobutyric acid ((14)C-MeAIB) mediated by system A amino acid transporter activity is increased at embryonic day 16 (E16), but this stimulation is not sustained, and by E19, fetal growth restriction (FGR) ensues. Here, we investigated whether upregulated (14)C-MeAIB transfer does occur concomitantly with a change in System A amino acid transporter activity and whether altered uteroplacental vascular function contributes to the FGR. We tested the hypothesis that FGR in P0 mice is attributable to altered nutrient transport rather than aberrant uteroplacental vascular function.

METHODS

Plasma membrane vesicles were isolated from placentas of P0 and wild-type (WT) fetuses at E16 and E19. System A amino acid transporter activity was measured as sodium-dependent (14)C-MeAIB uptake over 60s. Wire myography was performed on uterine artery branches supplying P0 or WT implantation sites and agonist-induced constriction and dilation measured.

RESULTS

Sodium-dependent uptake of (14)C-MeAIB (at 60s) was significantly (P < 0.05) higher in P0 compared to WT vesicles at E16; at E19 (14)C-MeAIB uptake was similar between P0 and WT. Uterine artery branch vascular reactivity was comparable between groups.

CONCLUSIONS

System A activity in the maternal-facing plasma membrane of syncytiotrophoblast layer II underpins the adaptations observed in the transplacental MeAIB flux of P0 mice. Unaltered uterine artery vascular function suggests that the FGR phenotype of P0 fetuses is primarily due to deficient placental nutrient exchange capacity.

Cerebral maturation in IUGR and appropriate for gestational age preterm babies

Intrauterine growth restriction (IUGR) is associated with increased risk of perinatal morbidity and mortality, as well as long-term neurological deficits. However, neurostructural correlations with observed developmental disabilities have not yet been established. Magnetic resonance imaging (MRI) could prove useful for assessing brain development in the early neonatal period. We evaluated cerebral lesions and morphological maturation by MRIs in 59 preterm neonates, in order to verify the hypothesis that IUGR interferes on human brain development. A total of 26 pregnancies were complicated by IUGR and 33 pregnancies delivered preterm at a comparable gestational age with appropriate for gestational age (AGA). Magnetic resonance examination was performed at the completion of 41 weeks' gestation. White matter disease studied with MR included periventricular cavitations and punctuate lesions characterized by increased signal on T1-weighted and decreased signal on T2-weighted images. Cerebral maturation was defined by the total maturation score, on the basis of 4 morphological parameters of cerebral maturation: myelination (M), cortical infolding (C), germinal matrix distribution (GM), and glial cell migration pattern (G). No difference in brain lesions and in the level of cerebral maturation was found between preterm AGA and IUGR neonates. However, myelination was significantly reduced in IUGR neonates with brain sparing compared to IUGR neonates with normal Doppler of middle cerebral artery. Our study could not demonstrate any major significant difference between preterm AGA and IUGR neonates in terms of lesion occurrence and cerebral maturation. We observed, however, a mild delay in myelination in IUGR with brain sparing in utero. The relevance of this finding needs to be investigated with long-term follow-up.

Vessel tortuousity and reduced vascularization in the fetoplacental arterial tree after maternal exposure to polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants and the main toxicants found in cigarettes. Women are often exposed to PAHs before pregnancy, typically via prepregnancy smoking. To determine how prepregnancy exposure affects the fetoplacental vasculature of the placenta, we exposed female mice to PAHs before conception, perfused the fetoplacental arterial trees with X-ray contrast agent, and imaged the vasculature ex vivo by microcomputed tomography (micro-CT) at embryonic day 15.5. Automated vascular segmentation and flow calculations revealed that in control trees, <40 chorionic plate vessels (diameter >180 μm) gave rise to ∼1,300 intraplacental arteries (50–180 μm), predicting an arterial vascular resistance of 0.37 ± 0.04 mmHg·s·μl−1. PAH exposure increased vessel curvature of chorionic plate vessels and significantly increased the tortuousity ratio of the tree. Intraplacental arteries were reduced by 17%, primarily due to a 27% decrease in the number of arteriole-sized (50–100 μm) vessels. There were no changes in the number of chorionic vessels, the depth or span of the tree, the diameter scaling coefficient, or the segment length-to-diameter ratio. PAH exposure resulted in a tree with a similar size and dichotomous branching structure, but one that was comparatively sparse so that arterial vascular resistance was increased by 30%. Assuming the same pressure gradient, blood flow would be 19% lower. Low flow may contribute to the 23% reduction observed in fetal weight. New insights into the specific effects of PAH exposure on a developing arterial tree were achieved using micro-CT imaging and automated vascular segmentation analysis.

A low-protein diet during gestation in rats activates the placental mammalian amino acid response pathway and programs the growth capacity of offspring

Placental efficiency is a predictor of fetal growth and development, which is also controlled by maternal gestational health and diet. The present study investigated the effects of a gestational low-protein diet on offspring growth capacity as well as the diet's contribution to altered expression of placental genes associated with the mammalian amino acid response (AAR) pathway. To assess these outcomes, timed-pregnant Sprague Dawley rats were fed a control (C) diet with 18% protein or a low-protein (LP) diet with 9% protein throughout gestation (Expt. 1) or throughout gestation and lactation (Expt. 2). Placentas were collected during natural delivery and quantitative RT-PCR and Western-blot analyses were performed to determine placental mRNA and protein levels. By the end of the lactation period, offspring of dams fed the LP diet had stunted growth in both experiments. mRNA expression of target genes in the AAR pathway, such as activating transcription factor-3 (Atf3), asparagine synthetase (Asns), and Sodium-dependent neutral amino acid transporter-2 (Snat2), was greater in placentas of rats fed the LP diet compared with controls, as were placental ATF4 and p-eIF2α protein levels. The increase in mRNA expression of AAR pathway-associated genes was correlated with the stunting of offspring growth (Atf3: R(2) = 0.32, P = 0.086; Asns: R(2) = 0.44, P < 0.05; Snat2: R(2) = 0.33, P = 0.084). Our study showed that the mammalian AAR pathway in placenta is upregulated by a maternal low-protein diet and this activation may act as a cue for the fetus to develop an adaptive response suited to their predicted postnatal environment, i.e. a more favorable phenotype for their survival.

Kisspeptin-10 inhibits angiogenesis in human placental vessels ex vivo and endothelial cells in vitro

Recent studies suggest that kisspeptin (a neuropeptide central to the regulation of gonadotrophin secretion) has diverse roles in human physiology, including a putative role in implantation and placental function. Kisspeptin and its receptor are present in human blood vessels, where they mediate vasoconstriction, and kisspeptin is known to inhibit tumor metastasis and trophoblast invasion, both processes involving angiogenesis. We hypothesized that kisspeptin contributes to the regulation of angiogenesis in the reproductive system. The presence of the kisspeptin receptor was confirmed in human placental blood vessels and human umbilical vein endothelial cells (HUVEC) using immunochemistry. The ability of kisspeptin-10 (KP-10) (a shorter biologically active processed peptide) to inhibit angiogenesis was tested in explanted human placental arteries and HUVEC using complementary ex vivo and in vitro assays. KP-10 inhibited new vessel sprouting from placental arteries embedded in Matrigel and tube-like structure formation by HUVEC, in a concentration-dependent manner. KP-10 had no effect on HUVEC viability or apoptosis but induced concentration-dependent inhibition of proliferation and migration. In conclusion, KP-10 has antiangiogenic effects and, given its high expression in the placenta, may contribute to the regulation of angiogenesis in this tissue.

Transferrin receptor gene and protein expression and localization in human IUGR and normal term placentas

Iron (Fe) deficiency in pregnancy is associated to low birth weight and premature delivery while in adults it can result in increased blood pressure and cardiovascular disease. Cellular Fe uptake is mediated by the Transferrin Receptor 1 (TFRC), located in the trophoblast membranes. Here, we measured TFRC mRNA expression (Real Time PCR) and TFRC protein expression and localization (Western Blotting and immunohistochemistry) in IUGR compared to control placentas. A total of 50 IUGR and 56 control placentas were studied at the time of elective cesarean section. IUGR was defined by ultrasound in utero, and confirmed by birth weight <10th percentile. Three different severity groups were identified depending on the umbilical artery pulsatility index and fetal heart rate. TFRC mRNA expression was significantly lower in IUGR placentas compared to controls (p < 0.05), and this was confirmed for TFRC protein levels. In both experiments the most severe IUGR group presented lower expression compared to the other groups, and this was also related to umbilical venous oxygen levels. TFRC protein localization in the villous trophoblast did not differ in the groups, and was predominantly present in the syncytiotrophoblast. In conclusion, these are the first observations about TFRC expression in human IUGR placentas, demonstrating its significant decrease in IUGR vs controls. Thus, Fe transport could be limited in IUGR placentas. Further studies are needed to study components of the placental Fe transport system and to clarify the regulation mechanisms involved in TFRC expression, possibly altered in IUGR placentas.

Obesity and the placenta: A consideration of nutrient exchange mechanisms in relation to aberrant fetal growth

The obesity epidemic, including childhood obesity, is rapidly gaining strength as one of the most significant challenges to the health of the global community in the 21st Century. The proportion of women who are obese at the beginning of pregnancy is also increasing. These women and their babies are at high risk of pregnancy complications, and of programming for metabolic disease in adult life. In particular, maternal obesity is associated with aberrant fetal growth, encompassing both growth restricted and large for gestational age, or macrosomic fetuses. This article considers the potential effect of obesity and adipose tissue on placental nutrient exchange mechanisms in relation to aberrant fetal growth. The review emphasizes the dearth of work on this topic to date despite its importance to current and future healthcare of the population.

Relationship between in utero sonographic evaluation and subcutaneous plicometry after birth in infants with intrauterine growth restriction: an exploratory study

Background

Intrauterine growth restriction (IUGR) is associated with several medical complications before and after delivery. The aim of this study was to evaluate the concordance between the fetal ultrasonographic measurement of subcutaneous tissue thicknesses and the skinfold thicknesses assessment in intrauterine growth restricted newborns.

Methods

We designed an exploratory study. Fetal ultrasonographic measurement of subcutaneous tissue thicknesses, according to Bernstein's and Galan's method, and neonatal skinfold thicknesses were evaluated in 13 intrauterine growth restricted newborns within 4 hours before delivery and on the first day of life, respectively. Concordance between fetal and neonatal measurements was assessed using the Lin's correlation coefficient and the Bland-Altman method.

Results

The data obtained by the measurements of neonatal skinfold thicknesses was significantly correlated with the prenatal measurements (Lin's coefficients, arm: 0.60; subscapular: 0.72; abdomen: 0.51). Bland-Altman analysis showed moderate agreement between the fetal ultrasonographic measurement of subcutaneous tissue thicknesses and the neonatal skinfold thicknesses assessment.

Conclusions

The present study provides preliminary evidence that fetal sonographic measurements may represent additional indices of intrauterine growth restriction.

Review and hypothesis: syndromes with severe intrauterine growth restriction and very short stature--are they related to the epigenetic mechanism(s) of fetal survival involved in the developmental origins of adult health and disease?

Diagnosing the specific type of severe intrauterine growth restriction (IUGR) that also has post-birth growth restriction is often difficult. Eight relatively common syndromes are discussed identifying their unique distinguishing features, overlapping features, and those features common to all eight syndromes. Many of these signs take a few years to develop and the lifetime natural history of the disorders has not yet been completely clarified. The theory behind developmental origins of adult health and disease suggests that there are mammalian epigenetic fetal survival mechanisms that downregulate fetal growth, both in order for the fetus to survive until birth and to prepare it for a restricted extra-uterine environment, and that these mechanisms have long lasting effects on the adult health of the individual. Silver-Russell syndrome phenotype has recently been recognized to be related to imprinting/methylation defects. Perhaps all eight syndromes, including those with single gene mutation origin, involve the mammalian mechanism(s) of fetal survival downsizing. Insights into those mechanisms should provide avenues to understanding the natural history, the heterogeneity and possible therapy not only for these eight syndromes, but for the common adult diseases with which IUGR is associated.

Transforming growth factor-{beta} (TGF{beta}) receptors I/II differentially regulate TGF{beta}1 and IGF-binding protein-3 mitogenic effects in the human placenta

Maternal IGFs regulate cytotrophoblast proliferation and, thereby, placental growth and function. IGF bioavailability is controlled by IGF-binding proteins (IGFBPs); in placenta, IGFBP-3 is particularly abundant. In other systems, IGFBP-3 can regulate cellular events independently of IGFs; these effects are thought to be mediated by TGFbeta receptors (TbetaR). We have examined IGFBP-3 regulation of IGF-dependent and -independent cytotrophoblast proliferation in first-trimester placental explants and the role of TbetaRII in mediating these effects. In the presence of IGFBP-3 (50 nm), IGF-induced (10 nm) proliferation (monitored by immunohistochemical analysis of Ki67 expression and bromodeoxyuridine incorporation) was significantly reduced (P < 0.05). IGFBP-3 also reduced basal proliferation independently of IGF receptor signaling. Immunohistochemical analysis demonstrated that TGFbeta signaling molecules [TGFbeta receptor I (TbetaRI), TbetaRII, TbetaRV, Smad-2, and ERK] are expressed in syncytium and/or cytotrophoblast. TGFbeta1 (10 ng/ml) enhanced cytotrophoblast proliferation and activated both Smad-2 and ERK-1/2, whereas IGFBP-3 activated only Smad-2. The function of both TGFbeta1 and IGFBP-3 was attenuated by a TbetaRII function-blocking antibody and by small interfering RNA-mediated knockdown of TbetaRII (P < 0.05); this was accompanied by a reduction in Smad-2 activation. This study demonstrates that both TGFbeta1 and IGFBP-3 signal through TbetaRI/II to influence human cytotrophoblast proliferation. However, downstream pathways are distinct, because IGFBP-3 acts only through Smad-2, whereas TGFbeta1 also phosphorylates ERK, resulting in opposite effects on cytotrophoblast proliferation. The effects of maternal growth signals on placental growth and function therefore depend on the balance of ligands, receptors, and signaling molecules at the syncytiotrophoblast surface. Therapeutic manipulation of this balance might offer a strategy to optimize placental development and pregnancy outcome.

Isolation of plasma membrane vesicles from mouse placenta at term and measurement of system A and system beta amino acid transporter activity

Placental amino acid transport is essential for optimal fetal growth and development, with a reduced fetal provision of amino acids being implicated as a potential cause of fetal growth restriction (FGR). Understanding placental insufficiency related FGR has been aided by the development of mouse models that have features of the human disease. However, to take maximal advantage of these, methods are required to study placental function in the mouse. Here, we report a method to isolate plasma membrane vesicles from mouse placenta near-term and have used these to investigate two amino acid transporters, systems A and β, the activities of which are reduced in human placental microvillous plasma membrane (MVM) vesicles from FGR pregnancies. Plasma membrane vesicles were isolated at embryonic day 18 by a protocol involving homogenisation, MgCl₂ precipitation and centrifugation. Vesicles were enriched 11.3 ± 0.5-fold in alkaline phosphatase activity as compared to initial homogenate, with minimal intracellular organelle contamination as judged by marker analyses. Cytochemistry revealed alkaline phosphatase was localised between trophoblast layers I and II, with intense reaction product deposited on the maternal-facing plasma membrane of layer II, suggesting that vesicles were derived from this trophoblast membrane. System A and system β activity in mouse placental vesicles, measured as Na⁺-dependent uptake of ¹⁴C-methylaminoisobutyric acid (MeAIB) and ³H-taurine respectively confirmed localisation of these transporters to the maternal-facing plasma membrane of layer II. Comparison to human placental MVM showed that system A activity was comparable at initial rate between species whilst system β activity was significantly lower in mouse. This mirrored the lower expression of TAUT observed in mouse placental vesicles. We conclude that syncytiotrophoblast layer II-derived plasma membrane vesicles can be isolated and used to examine transporter function.

Non-linear and gender-specific relationships among placental growth measures and the fetoplacental weight ratio

GOALS

Fetal growth depends on placental growth; the fetoplacental weight ratio (FPR) is a common proxy for the balance between fetal and placental growth. Male and female infants are known to have differing vulnerabilities in fetal life, during parturition and in infancy. We hypothesized that these differences may be paralleled by differences in how birth weight (BW) and the fetoplacental weight ratio (FPR) are affected by changes in placental proportions.

MATERIALS AND METHODS

Placental proportion measures (disk shape, larger and smaller chorionic diameters, chorionic plate area calculated as the area of an ellipse with the 2 given diameters, disk thickness, cord eccentricity and cord length) were available for 24,601 participants in the Collaborative Perinatal Project delivered between >34 and <43 completed weeks. The variables were standardized and entered into multiple automated regression splines (MARS 2.0, Salford Systems, Vista CA) to identify nonlinearities in the relationships of placental growth measures to BW and FPR with results compared for male and female infants.

RESULTS

Changes in chorionic plate growth in female compared to male infants resulted in a greater change in BW and FPR. The positive effects of umbilical cord length on BW reversed at the mean umbilical cord length in females and at +0.08 SD in male infants.

CONCLUSIONS

Female infants' BW and FPR are each more responsive to changes in placental chorionic plate growth dimensions than males; this may account for greater female resilience (and greater male vulnerability) to gestational stressors. The effect of umbilical cord length on FPR may be due to longer cords carrying greater fetal vascular resistance. Again male fetuses show a higher "threshold" to the negative effects of longer cords on FPR.

Insulin receptor isoforms and insulin receptor/insulin-like growth factor receptor hybrids in physiology and disease

In mammals, the insulin receptor (IR) gene has acquired an additional exon, exon 11. This exon may be skipped in a developmental and tissue-specific manner. The IR, therefore, occurs in two isoforms (exon 11 minus IR-A and exon 11 plus IR-B). The most relevant functional difference between these two isoforms is the high affinity of IR-A for IGF-II. IR-A is predominantly expressed during prenatal life. It enhances the effects of IGF-II during embryogenesis and fetal development. It is also significantly expressed in adult tissues, especially in the brain. Conversely, IR-B is predominantly expressed in adult, well-differentiated tissues, including the liver, where it enhances the metabolic effects of insulin. Dysregulation of IR splicing in insulin target tissues may occur in patients with insulin resistance; however, its role in type 2 diabetes is unclear. IR-A is often aberrantly expressed in cancer cells, thus increasing their responsiveness to IGF-II and to insulin and explaining the cancer-promoting effect of hyperinsulinemia observed in obese and type 2 diabetic patients. Aberrant IR-A expression may favor cancer resistance to both conventional and targeted therapies by a variety of mechanisms. Finally, IR isoforms form heterodimers, IR-A/IR-B, and hybrid IR/IGF-IR receptors (HR-A and HR-B). The functional characteristics of such hybrid receptors and their role in physiology, in diabetes, and in malignant cells are not yet fully understood. These receptors seem to enhance cell responsiveness to IGFs.

Placental efficiency and adaptation: endocrine regulation

Size at birth is critical in determining life expectancy and is dependent primarily on the placental supply of nutrients. However, the fetus is not just a passive recipient of nutrients from the placenta. It exerts a significant acquisitive drive for nutrients, which acts through morphological and functional adaptations in the placenta, particularly when the genetically determined drive for fetal growth is compromised by adverse intrauterine conditions. These adaptations alter the efficiency with which the placenta supports fetal growth, which results in optimal growth for prevailing conditions in utero. This review examines placental efficiency as a means of altering fetal growth, the morphological and functional adaptations that influence placental efficiency and the endocrine regulation of these processes.

Understanding placental nutrient transfer--why bother? New biomarkers of fetal growth

The placenta, in general and the physiology of maternofetal nutrient transfer is under-researched compared to other organs with epithelial transport function, as evidenced, for example, by publication numbers. This report provides reasons why more researchers should become involved in this topic. First, the syncytiotrophoblast, the transporting epithelium of the placenta, though having many basic cell physiology properties similar to those of other transporting epithelia, has several properties which are markedly different. Better information on these might help fundamental understanding of how epithelia in general function as well as improving knowledge of how the syncytiotrophoblast operates. Second, the synctiotrophoblast has a key role in controlling fetal growth, not only by transporting nutrients and waste products of metabolism but also because it increasingly appears to be one site, perhaps even the dominant site, in which integration of, sometimes conflicting, signals between mother and fetus takes place. Finally, better understanding of placental nutrient transfer and especially of how it is regulated by maternal and fetal signals could provide better information on the placental phenotype in fetal growth disorders--information which might contribute to providing better biomarkers which the obstetrician could use to improve early diagnosis of these disorders.

Regulation of amino acid transporters by glucose and growth factors in cultured primary human trophoblast cells is mediated by mTOR signaling

Inhibition of mammalian target of rapamycin (mTOR) signaling in cultured human primary trophoblast cells reduces the activity of key placental amino acid transporters. However, the upstream regulators of placental mTOR are unknown. We hypothesized that glucose, insulin, and IGF-I regulate placental amino acid transporters by inducing changes in mTOR signaling. Primary human trophoblast cells were cultured for 24 h with media containing various glucose concentrations, insulin, or IGF-I, with or without the mTOR inhibitor rapamycin, and, subsequently, the activity of system A, system L, and taurine (TAUT) transporters was measured. Glucose deprivation (0.5 mM glucose) did not significantly affect Thr172-AMP-activated protein kinase phosphorylation or REDD1 expression but decreased S6 kinase 1 phosphorylation at Thr389. The activity of system L decreased in a dose-dependent manner in response to decreasing glucose concentrations. This effect was abolished in the presence of rapamycin. Glucose deprivation had two opposing effects on system A activity: 1) an "adaptive" upregulation mediated by an mTOR-independent mechanism and 2) downregulation by an mTOR-dependent mechanism. TAUT activity was increased after incubating cells with glucose-deprived media, and this effect was largely independent of mTOR signaling. Insulin and IGF-I increased system A activity and insulin stimulated system L activity, effects that were abolished by rapamycin. We conclude that the mTOR pathway represents an important intracellular regulatory link between nutrient and growth factor concentrations and amino acid transport in the human placenta.

Long chain fatty acids and dietary fats in fetal nutrition

Long chain polyunsaturated fatty acids are essential nutrients for a healthy diet. The different kinds consumed by the mother during gestation and lactation may influence pregnancy, fetal and also neonatal outcome. The amount of fatty acids transferred from mother to fetus depends not only on maternal metabolism but also on placental function, i.e. by the uptake, metabolism and then transfer of fatty acids to the fetus. The third trimester of gestation is characterized by an increase of long chain polyunsaturated fatty acids in the fetal circulation, in particular docosahexaenoic acid, especially to support brain growth and visual development. These mechanisms may be altered in pathological conditions, such as intrauterine growth restriction and diabetes, when maternal and fetal plasma levels of long chain polyunsaturated fatty acids undergo significant changes. The aim of this review is to describe the maternal and placental factors involved in determining fetal fatty acid availability and metabolism, focusing on the specific role of long chain polyunsaturated fatty acids in normal and pathological pregnancies.

Placental gene expression profile in intrauterine growth restriction due to placental insufficiency

We evaluated global placental gene expression in intrauterine growth restriction (IUGR; n = 8) compared to normal pregnancies (n = 8) and studied possible additional effect of preeclampsia. Placental samples were collected from IUGR pregnancies due to placental insufficiency ascertained by hemodynamic studies. Four IUGR pregnancies were associated with preeclampsia. Gene expression profile was evaluated by 30k oligonucleotide microarrays. Principal component analysis (PCA) showed good separation in terms of gene expression patterns between the groups. Pathway analysis showed upregulation of inflammation mediated by chemokine and cytokine signaling pathway in the IUGR placentas. Genes involved in placental glucocorticoid metabolism were also differentially expressed. None of the known imprinted placental genes were differentially expressed. Subgroup analysis between IUGR placentas with and without preeclampsia showed few (n = 27) differentially expressed genes. In conclusion, IUGR due to placental insufficiency appears to alter placental glucocorticoid metabolism, upregulates inflammatory response in placenta, and shares common pathogenic mechanisms with severe early-onset preeclampsia.

Allometric metabolic scaling and fetal and placental weight

BACKGROUND

We tested the hypothesis that the fetal-placental relationship scales allometrically and identified modifying factors of that relationship.

MATERIALS AND METHODS

Among women delivering after 34 weeks but prior to 43 weeks' gestation, 24,601 participants in the Collaborative Perinatal Project (CPP) had complete data for placental gross proportion measures, specifically, placental weight (PW), disk shape, larger and smaller disk diameters and thickness, and umbilical cord length. The allometric metabolic equation was solved for alpha and beta by rewriting PW = alpha(BW)beta as ln(PW) = ln alpha + beta[ln(BW)]. alpha(iota) was then the dependent variable in regressions with p < 0.05 significant.

RESULTS

Mean beta was 0.78 + 0.02 (range 0.66, 0.89), which is consistent with the scaling exponent 0.75 predicted by Kleiber's Law. Gestational age, maternal age, maternal BMI, parity, smoking, socioeconomic status, infant sex, and changes in placental proportions each had independent and significant effects on alpha.

CONCLUSIONS

We find an allometric scaling relation between the placental weight and the birthweight in the CPP cohort with an exponent approximately equal to 0.75, as predicted by Kleiber's Law. This implies that: (1) placental weight is a justifiable proxy for fetal metabolic rate when other measures of fetal metabolic rate are not available; and (2) the allometric relationship between placental and birthweight is consistent with the hypothesis that the fetal-placental unit functions as a fractal supply limited system. Furthermore, our data suggest that the maternal and fetal variables we examined have at least part of their effects on the normal balance between placental weight and birth weight via effects on gross placental growth dimensions.

Amino acid transport systems beta and A in fetal T lymphocytes in intrauterine growth restriction and with tumor necrosis factor-alpha treatment

Intrauterine growth restriction (IUGR) is associated with reduced activity of placental amino acid transport systems beta and A. Whether this phenotype is maintained in fetal cells outside the placenta is unknown. In IUGR, cord blood tumor necrosis factor (TNF)-alpha concentrations are raised, potentially influencing amino acid transport in fetal cells. We used fetal T lymphocytes as a model to study systems beta and A amino acid transporters in IUGR compared with normal pregnancy. We also studied the effect of TNF-alpha on amino acid transporter activity. In fetal lymphocytes from IUGR pregnancies, taurine transporter mRNA expression encoding system beta transporter was reduced, but there was no change in system beta activity. No significant differences were observed in system A mRNA expression (encoding SNAT1 and SNAT2) or system A activity between the two groups. After 24 or 48 h TNF-alpha treatment, fetal T lymphocytes from normal pregnancies showed no significant change in system A or system beta activity, although cell viability was compromised. This study represents the first characterization of amino acid transport in a fetal cell outside the placenta in IUGR. We conclude that the reduced amino acid transporter activity found in placenta in IUGR is not a feature of all fetal cells.

Placental endoplasmic reticulum stress and oxidative stress in the pathophysiology of unexplained intrauterine growth restriction and early onset preeclampsia

The pregnancy complications of unexplained intrauterine growth restriction and early onset preeclampsia are thought to share a common aetiology in placental malperfusion secondary to deficient maternal spiral artery conversion. A key question is whether the contrasting clinical manifestations reflect different placental pathologies, or whether they are due to altered maternal responses to a common factor derived from the placenta. Recently, molecular evidence of protein synthesis inhibition secondary to endoplasmic reticulum stress has provided an explanation for the small placental phenotype in both conditions. However, other pathways activated by more severe endoplasmic reticulum stress are only observed in placentas from pregnancies associated with early onset preeclampsia. Here, we review the literature and conclude that there is evidence of greater maternal vascular compromise of the placenta in these cases. We speculate that in cases of normotensive intrauterine growth restriction the placental pathology is centred predominantly around endoplasmic reticulum stress, whereas in cases complicated by preeclampsia oxidative stress is further superimposed. This causes the release of a potent mix of pro-inflammatory cytokines, anti-angiogenic factors and trophoblastic aponecrotic debris into the maternal circulation that causes the peripheral syndrome. Maternal and fetal constitutional factors may modulate how the placenta responds to the maternal vascular insult, and how the mother is affected by the placental factors released. However, the principal conclusion is that the difference between these two conditions lies in the severity of the initiating deficit in spiral arterial conversion, and the relative degrees of endoplasmic reticulum stress and oxidative stress induced in the placenta as a result.

Maternal and fetal fatty acid profile in normal and intrauterine growth restriction pregnancies with and without preeclampsia

The aim of this study was to evaluate maternal and fetal lipid profile in intrauterine growth restriction (IUGR) pregnancies with and without preeclampsia (PE). Thirteen normal pregnancies studied during the third trimester (control M) and 29 at elective cesarean section (control CS) were compared with 18 pregnancies complicated by IUGR (IUGR only) and with seven pregnancies complicated by both IUGR and PE (IUGR-PE). Total plasma fatty acids, triglycerides, cholesterol, and nonesterified fatty acids (NEFA) were determined in maternal and fetal plasma. Nutritional intake was analyzed. IUGR only mothers had lower percentage of linoleic acid (LA) and higher arachidonic acid (AA) than controls, partly explained by higher AA dietary intake. Higher levels of NEFA were observed both in IUGR only and in IUGR-PE mothers whereas triglyceride levels were increased in IUGR-PE mothers only. In IUGR-PE fetuses, LA and AA were significantly decreased, whereas triglyceride and NEFA concentrations were significantly increased compared with normal fetuses. In conclusion, IUGR only is associated with altered fatty acids profile not completely accounted by dietary changes. We hypothesize that the differences observed in IUGR with PE for triglycerides and other lipids could be related to a difference in maternal phenotype.