Placental debris, oxidative stress and pre-eclampsia

Oxidative stress in pregnancy and reproduction

Oxidative stress is implicated in the pathophysiology of many reproductive complications including infertility, miscarriage, pre-eclampsia, fetal growth restriction and preterm labour. The presence of excess reactive oxygen species can lead to cellular damage of deoxyribonucleic acids, lipids and proteins. Antioxidants protect cells from peroxidation reactions, limiting cellular damage and helping to maintain cellular membrane integrity. There is overwhelming evidence for oxidative stress causing harm in reproduction. However, there is sparse evidence that supplementation with commonly used antioxidants (mostly vitamins C and E) makes any difference in overcoming oxidative stress or reversing disease processes. There may be potential for antioxidant therapy to ameliorate or prevent disease, but this requires a thorough understanding of the mechanism of action and specificity of currently used antioxidants.

The Regulation of Fatty Acid Oxidation in Human Preeclampsia

Preeclampsia (PE) is a pregnancy disorder characterized by high blood pressure, placental oxidative stress, and proteinuria. In a GeneFishing experiment using human preeclamptic placenta, expression of acyl-coenzyme A dehydrogenase very long chain (ACADVL), which is involved in fatty acid β-oxidation (FAO), was detected. To investigate the correlation between PE and FAO, this study subjected in vitro BeWo cells and in vivo pregnant mice to oxidative stress induced by hypoxia. Hypoxic condition, which oxygen supply is insufficient in cells and placenta, created a similar state to placental oxidative stress in PE, as evidenced by increased hypoxic (oxoguanine DNA glycosylase 1, hypoxia inducible factor 1 alpha subunit) and preeclamptic markers (soluble fms-like tyrosine kinase 1) both in vitro and in vivo. Increased expression of FAO-related genes (ACADVL, enoyl-coenzyme A hydratase/3-hydroxyacyl coenzyme A dehydrogenase) was observed in these models as well as in cases of preeclamptic preterm labor. In the in vivo liver model, messenger RNA expression of gluconeogenesis-related genes increased. Consequently, these results suggest that expression of FAO-related genes is regulated by hypoxic conditions and onset time of PE and affects maternal gluconeogenesis during pregnancy in patients with PE.

Early Prediction of Hypertensive Disorders of Pregnancy Using Cell-Free Fetal DNA, Cell-Free Total DNA, and Biochemical Markers

OBJECTIVE

To evaluate the predictive value of separate and combined tests using cell-free fetal DNA (cffDNA), cell-free total DNA (cfDNA), and biochemical markers for the early detection of pregnancies with hypertensive disorders.

METHODS

A nested case-control study was conducted with 135 singleton pregnancies including 17 gestational hypertension cases, 34 preeclampsia (PE) cases, and 84 controls. We performed real-time quantitative PCR to measure levels of DSCR3 and RASSF1A as cffDNA markers and HYP2 as a cfDNA marker in the first and early second trimesters. Levels of pregnancy-associated plasma protein A (PAPP-A), α-fetoprotein, β-human chorionic gonadotropin, unconjugated estriol, and inhibin A were also determined.

RESULTS

Compared with controls, the median levels and multiples of the median (MoM) values of HYP2 were significantly higher in the PE and hypertensive disorders of pregnancy (HDP) groups at 6-14 and 15-23 weeks. Frist-trimester PAPP-A MoM was significantly lower in PE and HDP than in controls. For PE and HDP, the best model included the first-trimester DSCR3, HYP2, and PAPP-A MoM values achieving detection rates of 67 and 58% at a fixed 10% false-positive rate, respectively [area under the receiver operating characteristic curve 0.832 (95% CI 0.689-0.928) for PE; 0.751 (0.607-0.863) for HDP].

DISCUSSION

The study demonstrates the potential utility of combined first-trimester cffDNA, cfDNA, and PAPP-A for the early prediction of PE.

Lack of Thromboxane Synthase Prevents Hypertension and Fetal Growth Restriction after High Salt Treatment during Pregnancy

Preeclampsia (PE) is a potentially fatal pregnancy-related hypertensive disorder characterized by poor placenta development that can cause fetal growth restriction. PE-associated pathologies, including thrombosis, hypertension, and impaired placental development, may result from imbalances between thromboxane A₂ (TXA₂) and prostacyclin. Low-dose aspirin, which selectively inhibits TXA₂ production, is used to prevent high-risk PE. However, the role of TXA₂ in aspirin-mediated protective effects in women with PE is not understood fully. In this study, we examined the role of prostanoids in PE using human samples and an induced PE mouse model. We demonstrated that the administration of salted drinking water (2.7% NaCl) to wild-type mice resulted in elevated placental TXA₂ synthase (TXAS) and plasma TXA₂, but not prostacyclin, levels, which was also found in our clinical PE placenta samples. The high salt-treated wild-type pregnant mice had shown unchanged maternal body weight, hypertension (MAP increase 15 mmHg), and decreased pup weight (~50%) and size (~24%), but these adverse effects were ameliorated in TXAS knockout (KO) mice. Moreover, increased expression of interleukin-1β and downstream phosphorylated-p38-mitogen-activated protein kinase were concordant with apoptosis induction in the placentas of salt water-treated wild-type mice. These alterations were not observed in TXAS KO mice. Together, our data suggest that TXA₂ depletion has anti-PE effects due to the prevention of hypertension and placental damage through downregulation of the interleukin-1β pathway.

Oxidative stress and the evolutionary origins of preeclampsia

In this speculative paper, I consider the relationship between oxidative stress and the evolution of placentation in eutherian mammals. I argue that epitheliochorial placentation, in which fetal tissues remain separated from maternal blood throughout gestation, has evolved as a protective mechanism against oxidative stress arising from pregnancy, particularly in species with unusually long gestation periods and unusually large placentas. Human beings comprise an unusual species that has the life history characteristics of an epitheliochorial species, but exhibits hemochorial placentation, in which fetal tissues come into direct contact with maternal blood. I argue that the risk of preeclampsia has arisen as a consequence of the failure of human beings to evolve epitheliochorial placentation.

Developmental aspects of a life course approach to healthy ageing

We examine the mechanistic basis and wider implications of adopting a developmental perspective on human ageing. Previous models of ageing have concentrated on its genetic basis, or the detrimental effects of accumulated damage, but also have raised issues about whether ageing can be viewed as adaptive itself, or is a consequence of other adaptive processes, for example if maintenance and repair processes in the period up to reproduction are traded off against later decline in function. A life course model places ageing in the context of the attainment of peak capacity for a body system, starting in early development when plasticity permits changes in structure and function induced by a range of environmental stimuli, followed by a period of decline, the rate of which depends on the peak attained as well as the later life conditions. Such path dependency in the rate of ageing may offer new insights into its modification. Focusing on musculoskeletal and cardiovascular function, we discuss this model and the possible underlying mechanisms, including endothelial function, oxidative stress, stem cells and nutritional factors such as vitamin D status. Epigenetic changes induced during developmental plasticity, and immune function may provide a common mechanistic process underlying a life course model of ageing. The life course trajectory differs in high and low resource settings. New insights into the developmental components of the life course model of ageing may lead to the design of biomarkers of later chronic disease risk and to new interventions to promote healthy ageing, with important implications for public health.

Effect of Placenta Previa on Preeclampsia

Background

The correlation between gestational hypertension-preeclampsia (GH-PE) and placenta previa (PP) is controversial. Specifically, it is unknown whether placenta previa has any effect on the various types of preeclampsia (PE), and the role PP with concurrent placenta accreta (PA) play in the occurrence of GH-PE are not well understood.

Objective

The aim of this study was to identify the effects of PP on GH, mild and severe preeclampsia (MPE and SPE), and early- and late-onset preeclampsia (EPE and LPE). Another aim of the study was to determine if concurrent PA impacts the relationship between PP and GH-PE.

Methods

A retrospective single-center study of 1,058 patients having singleton pregnancies with PP was performed, and 2,116 pregnant women were randomly included as controls. These cases were collected from a tertiary hospital and met the inclusion criteria for the study. Clinical information, including PP and the gestational age at the onset of GH-PE were collected. Binary and multiple logistic regression analyses were conducted after the confounding variables were controlled to assess the effects of PP on different types of GH-PE.

Results

There were 155 patients with GH-PE in the two groups. The incidences of GH-PE in the PP group and the control group were 2.5% (26/1058) and 6.1% (129/2116), respectively (P = 0.000). Binary and multiple regression analyses were conducted after controlling for confounding variables. Compared to the control group, in the PP group, the risk of GH-PE was reduced significantly by 78% (AOR: 0.216; 95% CI: 0.135–0.345); the risks of GH and PE were reduced by 55% (AOR: 0.451; 95% CI: 0.233–0.873) and 86% (AOR: 0.141; 95% CI: 0.073–0.271), respectively; the risks of MPE and SPE were reduced by 73% (AOR: 0.269; 95% CI: 0.087–0828) and 88% (AOR: 0.123; 95% CI: 0.055–0.279), respectively; and the risks of EPE and LPE were reduced by 95% (AOR: 0.047; 95% CI: 0.012–0.190) and 67% (AOR: 0.330; 95% CI: 0.153–0.715), respectively. The incidence of concurrent PA in women with PP was 5.86%; PP with PA did not significantly further reduce the incidence of GH-PE compared with PP without PA (1.64% vs. 2.51%, P>0.05). Binary logistic regression analyses were conducted after controlling for confounding variables, compared with the non-PP + GH-PE group, and the AOR of FGR in the non-PP + non-GH-PE group was 0.206 (0.124–0.342). Compared with the PP + GH-PE group, the AOR of FGR in the PP + non-GH-PE group was 0.430 (0.123–1.500).

Conclusion

PP is not only associated with a significant reduction in the incidence of GH-PE, but also is associated with a reduction in incidence of various types of PE. Concurrent PA and PP do not show association with a reduction in incidence of GH-PE.

Presence of Telocytes in a Non-innervated Organ: The Placenta

This chapter discusses the relationship between failure in placentation and the subsequent alterations in the normal structure of the placenta. Interstitial Cajal-like cells (ICLC) were observed for the first time in the human placenta in 2007 and later were named telocytes. Strong evidence confirms that in the placental chorionic villi, TC are located strategically between the smooth muscle cells (SMC) of the fetal blood vessel wall and the stromal myofibroblasts. As the placenta is a non-innervated organ and considering the strategic position of telocytes in chorionic villi, it has been postulated that their function would be related to signal transduction mechanisms involved in the regulation of the blood flow in the fetal vessels, as well as in the shortening/lengthening of the chorionic villi providing the necessary rhythmicity to the process of maternal/fetal metabolic exchange. In this context, telocytes represent part of a functional triad: "SMC of fetal blood vessel-telocyte-myofibroblast." This triad takes part in the regulation of fetal growth and development via transport of nutrients and gases. This chapter also discusses the alterations in the metabolic maternal-fetal exchange, leading to intrauterine growth retardation and preeclampsia. Additionally, the apoptosis undergoing in the preeclamptic hypoxic placenta affects all the chorionic villi cells, including telocytes and myofibroblast, and not only trophoblast, as it has been so far considered. In consequence, we proposed that apoptosis affects the triad structure and alters the placental function, subsequently affecting the normal fetal growth and development.

Glucocorticoid exposure in early placentation induces preeclampsia in rats via interfering trophoblast development

In pregnancy, placenta can be exposed to glucocorticoids (GCs) via several ways, which may disturb placentation and adversely affect pregnancy. Preeclampsia (PE) is thought to be attributed, in part, to impaired trophoblast development. The purpose of the present study was to confirm that GC exposure in early placentation could lead to PE in rats, with the mechanisms involving dysregulated trophoblast development. In the study, pregnant rats were administered with 2.5mg/kg Dex subcutaneously once per day from gestational day 7 to 13. Maternal systolic blood pressure and urinary albumin were increased, while both fetus and placenta were restricted after GC exposure relative to the control group. GC exposure also contributed to placental abnormalities and renal impairment. Moreover, placental oxidative damage was increased along with placental hypoxia-inducible factor 1-alpha (HIF1A) overexpression after GC treatment. Mechanically, GC induced PE in rat partially through inhibiting trophoblast proliferation, migration, invasion and epithelial-mesenchymal transition (EMT), which involved phospho-extracellular signal regulated kinase (p-ERK) downregulation. Furthermore, GC receptor was required for the inhibition of GC on trophoblast proliferation, migration, invasion and EMT in vitro. These findings suggest that GC exposure in early placentation could contribute to PE in pregnant rats, with the mechanisms involving inhibition of trophoblast proliferation, migration, invasion and EMT by GC.

Antiphospholipid antibodies bind syncytiotrophoblast mitochondria and alter the proteome of extruded syncytial nuclear aggregates

INTRODUCTION

Antiphospholipid antibodies (aPL) are autoantibodies that increase the risk of women developing the hypertensive disorder pre-eclampsia. aPL are internalised by the syncytiotrophoblast and increase extrusion of necrotic multinucleated syncytial nuclear aggregates (SNAs), which may trigger endothelial dysfunction in pre-eclampsia. The mechanisms by which aPL alter death processes in the syncytiotrophoblast leading to extrusion of SNAs are unknown.

METHODS

First trimester human placentae (n = 10) were dissected into explants and cultured either with aPL (50 μg/mL), isotype-matched control antibody (50 μg/mL), or media for 24 h. Harvested SNAs underwent iTRAQ proteomic analysis. Mitochondria in syncytiotrophoblast treated with aPL labelled with FluoroNanogold were visualised using transmission electron microscopy (TEM).

RESULTS

aPL altered the expression of 72 proteins in SNAs. Thirteen proteins were involved in mitochondrial function. TEM demonstrated that aPL bind to mitochondria in the syncytiotrophoblast and may cause mitochondrial swelling.

DISCUSSION

aPL disrupt mitochondria increasing the extrusion of SNAs with an altered proteome from the syncytiotrophoblast. These altered SNAs may trigger endothelial dysfunction and pre-eclampsia in these pregnancies.

Clinical characteristics of mirror syndrome: a comparison of 10 cases of mirror syndrome with non-mirror syndrome fetal hydrops cases

OBJECTIVE

To investigate clinical features of mirror syndrome.

METHODS

We retrospectively reviewed 71 cases of fetal hydrops with or without mirror syndrome, and compared with respect to maternal age, the body mass index, the primipara rate, the gestational age at delivery, the timing of fetal hydrops onset, the severity of fetal edema, placental swelling, the laboratory data and the fetal mortality. The data are expressed as the medians.

RESULTS

Mirror syndrome developed in 29% (10/35) of the cases with fetal hydrops. In mirror group, the onset time of fetal hydrops was significantly earlier (29 weeks versus 31 weeks, p = 0.011), and the severity of fetal hydrops (fetal edema/biparietal diameter) was significantly higher than non-mirror group (0.23 versus 0.16, p < 0.001). There was significantly higher serum human chorionic gonadotropin (hCG) (453,000 IU/L versus 80,000 IU/L, p < 0.001) and lower hemoglobin (8.9 g/dL versus 10.1 g/dL, p =0.002), hypoalbuminemia (2.3 mg/dL versus 2.7 mg/dL, p = 0.007), hyperuricemia (6.4 mg/dL versus 5.0 mg/dL, p = 0.043) in mirror group.

CONCLUSION

Mirror syndrome is occurred frequently in early and severe fetal hydrops and cause hemodilution and elevation of serum hCG.

Molecular Mechanisms of Preeclampsia

Preeclampsia is a pregnancy-specific disease characterized by new onset hypertension and proteinuria after 20 wk of gestation. It is a leading cause of maternal and fetal morbidity and mortality worldwide. Exciting discoveries in the last decade have contributed to a better understanding of the molecular basis of this disease. Epidemiological, experimental, and therapeutic studies from several laboratories have provided compelling evidence that an antiangiogenic state owing to alterations in circulating angiogenic factors leads to preeclampsia. In this review, we highlight the role of key circulating antiangiogenic factors as pathogenic biomarkers and in the development of novel therapies for preeclampsia.

Endoplasmic reticulum stress in the pathogenesis of early-onset pre-eclampsia

Recent data have provided molecular evidence of high levels of endoplasmic reticulum stress in non-laboured placentas from cases of early-onset pre-eclampsia. Endoplasmic reticulum stress is intricately linked to oxidative stress, and the two often share the same aetiology. In the case of pre-eclampsia this is likely to be placental malperfusion, secondary to deficient conversion of the spiral arteries. Endoplasmic reticulum stress activates a number of signalling pathways aimed at restoring homeostasis, but if these attempts fail then the apoptotic machinery may be activated. The potential consequences for placental development and function are numerous and diverse. Inhibition of protein synthesis results in lower levels of many kinases, growth factors and regulatory proteins involved in cell cycle control, and experiments in vitro reveal that endoplasmic reticulum stress slows cell proliferation. Chronic, low levels of stress during the second and third trimesters may therefore result in a growth restricted phenotype. Higher levels of endoplasmic reticulum stress lead to activation of pro-inflammatory pathways, a feature of pre-eclampsia that may contribute to maternal endothelial cell activation. These findings emphasise the complexity of cellular responses to stress, and the need to approach these in a holistic fashion when considering therapeutic interventions.

Biomarker development for presymptomatic molecular diagnosis of preeclampsia: feasible, useful or even unnecessary?

The past decade saw the advent of a number of promising biomarkers to detect pregnancies at risk for preeclampsia (PE), the foremost being those associated with an imbalance of angiogenic factors. In late pregnancy, these are useful for the detection of imminent cases of PE, while earlier they were more predictive for early- than late-onset PE. This suggests that there may be fundamental differences between the underlying pathology of these two PE forms. Therefore, it is possible that such a biological premise may limit the development of biomarkers that will permit the efficacious detection of both early- and late-onset PE via an analysis of first-trimester maternal blood samples. Consequently, a significant increase in our understanding of the underlying pathology of PE, using a variety of approaches ranging from systems biology to animal models, will be necessary in order to overcome this obstacle.

Full-length human placental sFlt-1-e15a isoform induces distinct maternal phenotypes of preeclampsia in mice

OBJECTIVE

Most anti-angiogenic preeclampsia models in rodents utilized the overexpression of a truncated soluble fms-like tyrosine kinase-1 (sFlt-1) not expressed in any species. Other limitations of mouse preeclampsia models included stressful blood pressure measurements and the lack of postpartum monitoring. We aimed to 1) develop a mouse model of preeclampsia by administering the most abundant human placental sFlt-1 isoform (hsFlt-1-e15a) in preeclampsia; 2) determine blood pressures in non-stressed conditions; and 3) develop a survival surgery that enables the collection of fetuses and placentas and postpartum (PP) monitoring.

METHODS

Pregnancy status of CD-1 mice was evaluated with high-frequency ultrasound on gestational days (GD) 6 and 7. Telemetry catheters were implanted in the carotid artery on GD7, and their positions were verified by ultrasound on GD13. Mice were injected through tail-vein with adenoviruses expressing hsFlt-1-e15a (n = 11) or green fluorescent protein (GFP; n = 9) on GD8/GD11. Placentas and pups were delivered by cesarean section on GD18 allowing PP monitoring. Urine samples were collected with cystocentesis on GD6/GD7, GD13, GD18, and PPD8, and albumin/creatinine ratios were determined. GFP and hsFlt-1-e15a expression profiles were determined by qRT-PCR. Aortic ring assays were performed to assess the effect of hsFlt-1-e15a on endothelia.

RESULTS

Ultrasound predicted pregnancy on GD7 in 97% of cases. Cesarean section survival rate was 100%. Mean arterial blood pressure was higher in hsFlt-1-e15a-treated than in GFP-treated mice (∆MAP = 13.2 mmHg, p = 0.00107; GD18). Focal glomerular changes were found in hsFlt-1-e15a -treated mice, which had higher urine albumin/creatinine ratios than controls (109.3 ± 51.7 μg/mg vs. 19.3 ± 5.6 μg/mg, p = 4.4 x 10(-2); GD18). Aortic ring assays showed a 46% lesser microvessel outgrowth in hsFlt-1-e15a-treated than in GFP-treated mice (p = 1.2 x 10(-2)). Placental and fetal weights did not differ between the groups. One mouse with liver disease developed early-onset preeclampsia-like symptoms with intrauterine growth restriction (IUGR).

CONCLUSIONS

A mouse model of late-onset preeclampsia was developed with the overexpression of hsFlt-1-e15a, verifying the in vivo pathologic effects of this primate-specific, predominant placental sFlt-1 isoform. HsFlt-1-e15a induced early-onset preeclampsia-like symptoms associated with IUGR in a mouse with a liver disease. Our findings support that hsFlt-1-e15a is central to the terminal pathway of preeclampsia, and it can induce the full spectrum of symptoms in this obstetrical syndrome.

Activation of villous trophoblastic p38 and ERK1/2 signaling pathways in preterm preeclampsia and HELLP syndrome

Preterm preeclampsia is associated with the failure of trophoblast invasion, placental hypoxic/ischemic injury and the release of toxic substances, which promote the terminal pathway of preeclampsia. In term preeclampsia, factors yet unknown trigger the placenta to induce the terminal pathway. The contribution of the villous trophoblast to these pathologic events has not been fully elucidated. Here we aimed to study how stress and signaling pathways influence trophoblastic functions in various subforms of preeclampsia. Tissue microarrays (TMAs) were constructed from placentas obtained from pregnant women in the following groups: 1-2) preterm preeclampsia with (n = 8) or without (n = 7) HELLP syndrome; 3) late-onset preeclampsia (n = 8); 4-5) preterm (n = 5) and term (n = 9) controls. TMA slides were stained for phosphorylated Akt-1, ERK1/2, JNK, and p38 kinases, and trophoblastic immunostainings were semi-quantitatively evaluated. BeWo cells were kept in various stress conditions, and the expression of FLT1, GCM1, LEP, and PGF was profiled by qRT-PCR, while Akt-1, ERK1/2, JNK, and p38 kinase activities were measured with phospho-kinase immunoassays. We found that: 1) Placental LEP and FLT1 expression was up-regulated in preterm preeclampsia with or without HELLP syndrome compared to controls; 2) Mean pp38 immunoscore was higher in preterm preeclampsia, especially in cases with HELLP syndrome, than in controls. 3) Mean pERK1/2 immunoscore was higher in preterm preeclampsia with HELLP syndrome than in controls. 4) In BeWo cells, ischemia up-regulated LEP expression, and it increased JNK and decreased ERK1/2 activity. 5) Hypoxia up-regulated FLT1 and down-regulated PGF expression, and it increased ERK1/2, JNK and p38 activity. 6) IL-1β treatment down-regulated PGF expression, and it increased JNK and p38 activity. 7) The p38 signaling pathway had the most impact on LEP, FLT1 and PGF expression. In conclusion, hypoxic and ischemic stress, along with unknown factors, activates trophoblastic p38 signaling, which has a key role in villous trophoblastic functional changes in preterm preeclampsia. The activation of ERK1/2 signaling may induce additional trophoblastic functional changes in HELLP syndrome, while distinct mechanisms may promote late-onset preeclampsia.

Reduced expression of the epidermal growth factor signaling system in preeclampsia

INTRODUCTION

The epidermal growth factor (EGF) signaling system regulates trophoblast differentiation, and its disruption could contribute to perinatal disease. We hypothesized that this pathway is altered in preeclampsia, a disorder associated with trophoblast apoptosis and failure to invade and remodel the uterine spiral arteries.

METHODS

Six EGF family peptides and a truncated EGF receptor splice variant (p110/EGFR) were examined using immunohistochemistry in the trophoblast of placentas (N = 76) from women with preeclampsia, and compared to placentas from women of similar gestational age (GA) with preterm labor (PTL) or small for gestational age (SGA) fetuses, as well as normal term placentas. EGF, transforming growth factor-α (TGFA), and heparin-binding EGF-like growth factor (HBEGF) were evaluated using ELISA in maternal plasma from another 20 pregnancies with or without preeclampsia. Cell death was evaluated in the HTR-8/SVneo human cytotrophoblast cell line using TUNEL to evaluate the protective effects of EGF peptides.

RESULTS

Trophoblast HBEGF, TGFA, and EGF were significantly reduced in preeclampsia compared to PTL and SGA, while p110/EGFR accumulated significantly on the surface of the chorionic villi (p < 0.05). Plasma EGF levels were significantly decreased in preeclamptic patients, compared to non-preeclamptic patients (p < 0.05). HBEGF, EGF, TGFA, epiregulin, and betacellulin each blocked cytotrophoblast cell death in vitro (p < 0.05).

DISCUSSION

Three members of the EGF family are dysregulated in placentas with preeclampsia, whereas p110/EGFR, a potential EGF receptor antagonist, is overexpressed. These findings are consistent with the concept that disruption of the EGF signaling system contributes to aberrant trophoblast development associated with preeclampsia.

In vivo experiments reveal the good, the bad and the ugly faces of sFlt-1 in pregnancy

Objective

Soluble fms-like tyrosine kinase (sFlt)-1-e15a, a primate-specific sFlt-1-isoform most abundant in the human placenta in preeclampsia, can induce preeclampsia in mice. This study compared the effects of full-length human (h)sFlt-1-e15a with those of truncated mouse (m)sFlt-1(1-3) used in previous preeclampsia studies on pregnancy outcome and clinical symptoms in preeclampsia.

Methods

Mice were injected with adenoviruses or fiber-mutant adenoviruses overexpressing hsFlt-1-e15a, msFlt-1(1-3) or control GFP under the CMV or CYP19A1 promoters on gestational day 8 (GD8) and GD11. Placentas and pups were delivered by cesarean section, and dams were monitored postpartum. Blood pressure was telemetrically recorded. Urine samples were collected with cystocentesis and examined for albumin/creatinine ratios. Tissue specimens were evaluated for transgene as well as endogenous mFlt-1 and msFlt-1-i13 expression. H&E-, Jones- and PAS-stained kidney sections were histopathologically examined. Placental GFP expression and aortic ring assays were investigated with confocal microscopy.

Results

Mean arterial blood pressure (MAP) was elevated before delivery in hsFlt-1-e15a-treated mice compared to controls (GD18: ΔMAP = 7.8 mmHg, p = 0.009), while ΔMAP was 12.8 mmHg (GD18, p = 0.005) in msFlt-1(1-3)-treated mice. Urine albumin/creatinine ratio was higher in hsFlt-1-e15a-treated mice than in controls (GD18, p = 0.04; PPD8, p = 0.03), and msFlt-1(1-3)-treated mice had marked proteinuria postpartum (PPD8, p = 4×10⁻⁵). Focal glomerular changes were detected in hsFlt-1-e15a and msFlt-1(1-3)-treated mice. Aortic ring microvessel outgrowth was decreased in hsFlt-1-e15a (p = 0.007) and msFlt-1(1-3)-treated (p = 0.02) mice. Full-length msFlt-1-i13 expression was unique for the placenta. In hsFlt-1-e15a-treated mice, the number of pups (p = 0.046), total weight of living pups (p = 0.04) and maternal weights (p = 0.04) were higher than in controls. These differences were not observed in truncated msFlt-1(1-3)-treated mice.

Conclusions

Truncated msFlt-1(1-3) simulated the preeclampsia-promoting effects of full-length hsFlt-1. MsFlt-1(1-3) had strong effect on maternal endothelium but not on placentas and embryos. In contrast, hsFlt-1-e15a induced preeclampsia-like symptoms; however, it also increased litter size. In accord with the predominant placental expression of hsFlt-1-e15a and msFlt-1-i13, full-length sFlt-1 may have a role in the regulation of embryonic development. These observations point to the difference in the biological effects of full-length and truncated sFlt-1 and the changes in the effect of full-length sFlt-1 during pregnancy, and may have important implications in the management of preeclampsia.

Maternal plasma fetuin-A concentration is lower in patients who subsequently developed preterm preeclampsia than in uncomplicated pregnancy: a longitudinal study

Objective: Fetuin-A is a negative acute phase protein reactant that acts as a mediator for lipotoxicity, leading to insulin resistance. Intravascular inflammation and insulin resistance have been implicated in the mechanisms of disease responsible for preeclampsia (PE). Maternal plasma concentrations of fetuin-A at the time of diagnosis of preterm PE are lower than in control patients with a normal pregnancy outcome. However, it is unknown if the changes in maternal plasma fetuin-A concentrations precede the clinical diagnosis of the disease. We conducted a longitudinal study to determine whether patients who subsequently developed PE had a different profile of maternal plasma concentrations of fetuin-A as a function of gestational age (GA) than those with uncomplicated pregnancies. Methods: A longitudinal case-control study was performed and included 200 singleton pregnancies in the following groups: (1) patients with uncomplicated pregnancies who delivered appropriate for gestational age (AGA) neonates (n = 160); and (2) patients who subsequently developed PE (n = 40). Longitudinal samples were collected at each prenatal visit and scheduled at 4-week intervals from the first or early second trimester until delivery. Plasma fetuin-A concentrations were determined by ELISA. Analysis was performed using mixed-effects models. Results: The profiles of maternal plasma concentrations of fetuin-A differ between PE and uncomplicated pregnancies. Forward analysis indicated that the rate of increase of plasma fetuin-A concentration in patients who subsequently developed PE was lower at the beginning of pregnancy (p = 0.001), yet increased faster mid-pregnancy (p = 0.0017) and reached the same concentration level as controls by 26 weeks. The rate of decrease was higher towards the end of pregnancy in patients with PE than in uncomplicated pregnancies (p = 0.002). The mean maternal plasma fetuin-A concentration was significantly lower in patients with preterm PE at the time of clinical diagnosis than in women with uncomplicated pregnancies (p < 0.05). In contrast, there were no significant differences in maternal plasma fetuin-A concentration in patients who developed PE at term. Conclusions: (1) The profile of maternal plasma concentrations of fetuin-A over time (GA) in patients who develop PE is different from that of normal pregnant women; (2) the rate of change of maternal plasma concentrations of fetuin-A is positive (increases over time) in the midtrimester of normal pregnancy, and negative (decreases over time) in patients who subsequently develop PE; (3) at the time of diagnosis, the maternal plasma fetuin-A concentration is lower in patients with preterm PE than in those with a normal pregnancy outcome; however, such differences were not demonstrable in patients with term PE.

Uterine artery Doppler, birth weight and timing of onset of pre-eclampsia: providing insights into the dual etiology of late-onset pre-eclampsia

OBJECTIVE

To investigate the relationship between uterine artery Doppler ultrasound indices and birth weight in women with early-, intermediate- and late-onset pre-eclampsia as compared with women with uneventful pregnancy outcome.

METHODS

In a retrospective, observational cohort study, uterine artery Doppler assessment was carried out at 18+0 to 23+6 weeks' gestation in 26,893 women attending for routine antenatal care in a tertiary care center. The mean resistance index (RI) and its relationship to the outcome of pregnancy and birth-weight centiles were evaluated.

RESULTS

Uterine artery RI showed a significant, negative correlation with birth weight (r= -0.20, P<0.0001). Patients with early-onset pre-eclampsia had an increased prevalence of high uterine artery mean RI, above the 90(th) centile, corresponding to an increased proportion of small-for-gestational age (SGA) neonates with a birth weight below the 10(th) centile. In late-onset pre-eclampsia, however, there was an unexpectedly higher proportion of large-for-gestational-age (LGA) neonates with a birth weight above the 90(th) centile without a concurrent increase in the prevalence of low uterine artery mean RI below the 10(th) centile.

CONCLUSIONS

The finding of a bimodal skewed distribution of birth weight, with neonates exhibiting a higher prevalence of both LGA and SGA with late-onset pre-eclampsia, indicates that there are two types of late-onset pre-eclampsia. These findings explain the poor performance of mid-trimester uterine artery Doppler in predicting pre-eclampsia at term and provide insights into the placental origins of the early and late forms of pre-eclampsia.

Differential activation of placental unfolded protein response pathways implies heterogeneity in causation of early- and late-onset pre-eclampsia

Based on gestational age at diagnosis and/or delivery, pre-eclampsia (PE) is commonly divided into early-onset (<34 weeks) and late-onset (≥34 weeks) forms. Recently, the distinction between ‘placental’ and ‘maternal’ causation has been proposed, with ‘placental’ cases being more frequently associated with early-onset and intrauterine growth restriction. To test whether molecular placental pathology varies according to clinical presentation, we investigated stress-signalling pathways, including unfolded protein response (UPR) pathways, MAPK stress pathways, heat-shock proteins and AMPKα in placentae delivered by caesarean section for clinical indications at different gestational ages. Controls included second-trimester, pre-term and normal-term placentae. BeWo cells were used to investigate how these pathways react to different severities of hypoxia–reoxygenation (H/R) and pro-inflammatory cytokines. Activation of placental UPR and stress-response pathways, including P-IRE1α, ATF6, XBP-1, GRP78 and GRP94, P-p38/p38 and HSP70, was higher in early-onset PE than in both late-onset PE and normotensive controls (NTCs), with a clear inflection around 34 weeks. Placentae from ≥ 34 weeks PE and NTC were indistinguishable. Levels of UPR signalling were similar between second-trimester and term controls, but were significantly higher in pre-term ‘controls’ delivered vaginally for chorioamnionitis and other conditions. Severe H/R (1/20% O₂) induced equivalent activation of UPR pathways, including P-eIF2α, ATF6, P-IRE1α, GRP78 and GRP94, in BeWo cells. By contrast, the pro-inflammatory cytokines TNFα and IL-1β induced only mild activation of P-eIF2α and GRP78. AKT, a central regulator of cell proliferation, was reduced in the < 34 weeks PE placentae and severe H/R-treated cells, but not in other conditions. These findings provide the first molecular evidence that placental stress may contribute to the pathophysiology of early-onset pre-eclampsia, whereas that is unlikely to be the case in the late-onset form of the syndrome. © 2014 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Hypoxic treatment of human dual placental perfusion induces a preeclampsia-like inflammatory response

Preeclampsia is a human pregnancy-specific disorder characterized by a placental pro-inflammatory response in combination with an imbalance of angiogenic factors and clinical symptoms, including hypertension and proteinuria. Insufficient uteroplacental oxygenation in preeclampsia due to impaired trophoblast invasion during placentation is believed to be responsible for many of the molecular events leading to the clinical manifestations of this disease. We investigated the use of hypoxic treatment of the dual placental perfusion system as a model for preeclampsia. A modified perfusion technique allowed us to achieve a mean soluble oxygen tension within the intervillous space (IVS) of 5-7% for normoxia and <3% for hypoxia (as a model for preeclampsia). We assayed for the levels of different inflammatory cytokines, oxidative stress markers, as well as other factors, such as endothelin (ET)-1 that are known to be implicated as part of the inflammatory response in preeclampsia. Our results show a significant increase under hypoxia in the levels of different inflammatory cytokines, including IL-6 (P=0.002), IL-8 (P<0.0001), TNF-α (P=0.032) and IFN-γ (P=0.009) at 360 min in maternal venous samples (n=6). There was also a significant increase in ET-1 levels under hypoxia both on the maternal side at 30 min (P=0.003) and fetal side at 360 min (P=0.036) (n=6). Other markers of oxidative stress, including malondialdehyde and 8-iso-protaglandin F2α (P=0.009) also show increased levels. Overall, these findings indicate that exposure of ex vivo dually perfused placental tissue to hypoxia provides a useful model for mimicking the inflammatory response characteristic of preeclampsia. This would therefore provide a powerful tool for studying and further delineating the molecular mechanisms involved in the underlying pathophysiology of preeclampsia.

Abnormal oxidative stress responses in fibroblasts from preeclampsia infants

Background

Signs of severe oxidative stress are evident in term placentae of infants born to mothers with preeclampsia (PE), but it is unclear whether this is a cause or consequence of the disease. Here fibroblast lines were established from umbilical cords (UC) delivered by mothers who had experienced early onset PE and from controls with the goal of converting these primary cells to induced pluripotent stem cells and ultimately trophoblast. Contrary to expectations, the oxidative stress responses of these non-placental cells from PE infants were more severe than those from controls.

Methods and Findings

Three features suggested that UC-derived fibroblasts from PE infants responded less well to oxidative stressors than controls: 1) While all UC provided outgrowths in 4% O₂, success was significantly lower for PE cords in 20% O₂; 2) PE lines established in 4% O₂ proliferated more slowly than controls when switched to 20% O₂; 3) PE lines were more susceptible to the pro-oxidants diethylmaleate and tert-butylhydroquinone than control lines, but, unlike controls, were not protected by glutathione. Transcriptome profiling revealed only a few genes differentially regulated between PE lines and controls in 4% O₂ conditions. However, a more severely stressed phenotype than controls, particularly in the unfolded protein response, was evident when PE lines were switched suddenly to 20% O₂, thus confirming the greater sensitivity of the PE fibroblasts to acute changes in oxidative stress.

Conclusions

UC fibroblasts derived from PE infants are intrinsically less able to respond to acute oxidative stress than controls, and this phenotype is retained over many cell doublings. Whether the basis of this vulnerability is genetic or epigenetic and how it pertains to trophoblast development remains unclear, but this finding may provide a clue to the basis of the early onset, usually severe, form of PE.

Role of lectin-like oxidized low density lipoprotein-1 in fetoplacental vascular dysfunction in preeclampsia

The bioavailability of nitric oxide (NO) represents a key marker in vascular health. A decrease in NO induces a pathological condition denominated endothelial dysfunction, syndrome observed in different pathologies, such as obesity, diabetes, kidney disease, cardiovascular disease, and preeclampsia (PE). PE is one of the major risks for maternal death and fetal loss. Recent studies suggest that the placenta of pregnant women with PE express high levels of lectin-like oxidized LDL receptor-1 (LOX-1), which induces endothelial dysfunction by increasing reactive oxygen species (ROS) and decreasing intracellular NO. Besides LOX-1 activation induces changes in migration and apoptosis of syncytiotrophoblast cells. However, the role of this receptor in placental tissue is still unknown. In this review we will describes the physiological roles of LOX-1 in normal placenta development and the potential involvement of this receptor in the pathophysiology of PE.

Monocytes and macrophages in pregnancy and pre-eclampsia

Preeclampsia is an important complication in pregnancy, characterized by hypertension and proteinuria in the second half of pregnancy. Generalized activation of the inflammatory response is thought to play a role in the pathogenesis of pre-eclampsia. Monocytes may play a central role in this inflammatory response. Monocytes are short lived cells that mature in the circulation and invade into tissues upon an inflammatory stimulus and develop into macrophages. Macrophages are abundantly present in the endometrium and play a role in implantation and placentation in normal pregnancy. In pre-eclampsia, these macrophages appear to be present in larger numbers and are also activated. In the present review, we focused on the role of monocytes and macrophages in the pathophysiology of pre-eclampsia.

Expression of lipoxin A4, TNFα and IL-1β in maternal peripheral blood, umbilical cord blood and placenta, and their significance in pre-eclampsia

OBJECTIVE

The purpose of this study was to investigate the expression of lipoxin A4, TNFα and IL-1β in maternal peripheral blood, umbilical cord blood and placenta, and to assess their significance in pre-eclampsia.

METHODS

Ninty pregnant women were divided into three groups: a mild PE group (n = 30), a severe PE group (n = 30) and a control group (n = 30). We measured serum levels of lipoxin A4, TNFα and IL-1β using ELISA. Expression levels of lipoxin receptor (FPR2/ALX) mRNA were compared using quantitative RT-PCR.

RESULTS

Mean circulating levels of lipoxin A4, TNFα and IL-1β in the PE groups were significantly increased compared with matched women in the control group. The ratios of lipoxin A4/TNFα and of lipoxin A4/IL-1β in the PE groups were significantly decreased compared with matched women in the control group. No lipoxin A4 was detected in umbilical cord blood. There was a significant increase in FPR2/ALX mRNA expression in placenta obtained from the PE groups.

CONCLUSIONS

The level of lipoxin A4 in maternal peripheral blood may correlate with the expression of FPR2/ALX in placenta. Lipoxin A4 increased to a lesser degree than either TNFα or IL-1β with progression of PE. This may be one of the reasons why oxidative stress and endothelial dysfunction in severe preeclamptic patients are much more serious that in cases of less severe preeclampsia. Moreover, lipoxin A4 does not have any effect on the fetus through the placenta. We conclude that supplementing with lipoxin A4 to ensure adequate levels may be a novel method for the treatment of pre-eclampsia without any effects on the fetus.

Can the quantity of cell-free fetal DNA predict preeclampsia: a systematic review

OBJECTIVE

Previous studies have demonstrated an increase in the quantity of cell-free fetal DNA (cffDNA) before the onset of preeclampsia. It would be beneficial if the quantity of cffDNA predicted preeclampsia in order to implement preventative trials and strategies to decrease maternal and fetal morbidity. Our objective was to review the literature on using cffDNA levels as a predictor of preeclampsia.

METHODS

We performed a systematic review following the Meta-analyses and Systematic Review of Observational Studies guidelines. Included studies evaluated cffDNA levels in pregnant women before the clinical onset of preeclampsia.

RESULTS

Thirteen studies met inclusion criteria. There was considerable heterogeneity between included studies, and all received a quality grade of C on the Grading of Recommendations Assessment, Development, and Evaluation scale. Of the 13 studies, 11 found an increase in cffDNA among pregnant women who subsequently developed preeclampsia. In addition, all four studies analyzing early-onset or severe preeclampsia found significantly elevated cffDNA levels prior to disease onset.

CONCLUSION

Cell-free fetal DNA quantification is a promising marker for preeclampsia prediction, especially for the development of early-onset or severe preeclampsia. However, because of the heterogeneity in published studies, a precise conclusion about the statistical and clinical relevance cannot be made.

The therapeutic potential of antioxidants, ER chaperones, NO and H2S donors, and statins for treatment of preeclampsia

Preeclampsia is a complex multifactorial disease. Placental oxidative stress, a result of deficient spiral artery remodeling, plays an important role in the pathophysiology of preeclampsia. Antiangiogenic factors secreted from malperfused placenta are instrumental in mediating maternal endothelial dysfunction and consequent symptoms of preeclampsia; the mechanism is likely to involve increased ET-1 secretion and reduced NO bioavailability. Therapeutic interventions so far remain only experimental and there is no established remedy for the treatment of preeclampsia. This review concentrates on the evidence for the therapeutic potential of antioxidants, ER chaperones, NO and H2S donors, and statins. These compounds display pleitropic antioxidant, anti-inflammatory, and pro-angiogenic effects in animal and in vitro studies. Although clinical trials on the use of antioxidant vitamins in pregnancy proved largely unsuccessful, the scope for their use still exists given the beneficial cardioprotective effects of antioxidant-rich Mediterranean diet, periconceptual vitamin use and the synergistic effect of vitamin C and L-arginine. Encouraging clinical evidence exists for the use of NO donors, and a clinical trial is underway testing the effect of statins in treatment of preeclampsia. H2S recently emerged as a novel therapeutic agent for cardiovascular disease, and its beneficial effects were also tested in animal models of preeclampsia. It is risky to prescribe any medication to pregnant women on a large scale, and any future therapeutic intervention has to be well tested and safe. Many of the compounds discussed could be potential candidates.

Controlling the Immunological Crosstalk during Conception and Pregnancy: HLA-G in Reproduction

In several years after its discovery in the placenta, the human leukocyte antigen (HLA) class Ib protein, HLA-G, was not given much attention, nor was it assigned great importance. As time has unraveled, HLA-G has proven to have distinctive functions and an unforeseen and possibly important role in reproduction. HLA-G is characterized mainly by its low polymorphism and restricted tissue distribution in non-pathological conditions. In fact, its expression pattern is primarily limited to extravillous cytotrophoblast cells at the maternal-fetal interface during pregnancy. Due to low polymorphism, almost the same protein is expressed by virtually all individuals. It is these unique features that make HLA-G differ from its highly polymorphic HLA class Ia counterparts, the HLA-A, -B, and -C molecules. Its function, seemingly diverse, is typically receptor-mediated, and involves interactions with a wide range of immune cells. As the expression of HLA-G primarily is limited to gestation, this has given rise to the hypothesis that HLA-G plays an important role in the immunological tolerance of the fetus by the mother. In keeping with this, it might not be surprising that polymorphisms in the HLA-G gene, and levels of HLA-G expression, have been linked to reproductive failure and pre-eclampsia. Based on recent studies, we speculate that HLA-G might be involved in mechanisms in reproductive immunology even before conception because HLA-G can be detected in the genital tract and in the blood of non-pregnant women, and is present in seminal fluid from men. In addition, HLA-G expression has been found in the pre-implanted embryo. Therefore, we propose that a combined contribution from the mother, the father, and the embryo/fetus is likely to be important. Furthermore, this review presents important aspects of HLA-G in relation to reproduction: from genetics to physiological effects, from pregnancy and pregnancy complications to a short discussion on future possible means of preventative measures and therapy.

Effect of selenium on markers of risk of pre-eclampsia in UK pregnant women: a randomised, controlled pilot trial

Pre-eclampsia is a serious hypertensive condition of pregnancy associated with high maternal and fetal morbidity and mortality. Se intake or status has been linked to the occurrence of pre-eclampsia by our own work and that of others. We hypothesised that a small increase in the Se intake of UK pregnant women of inadequate Se status would protect against the risk of pre-eclampsia, as assessed by biomarkers of pre-eclampsia. In a double-blind, placebo-controlled, pilot trial, we randomised 230 primiparous pregnant women to Se (60 μg/d, as Se-enriched yeast) or placebo treatment from 12 to 14 weeks of gestation until delivery. Whole-blood Se concentration was measured at baseline and 35 weeks, and plasma selenoprotein P (SEPP1) concentration at 35 weeks. The primary outcome measure of the present study was serum soluble vascular endothelial growth factor receptor-1 (sFlt-1), an anti-angiogenic factor linked with the risk of pre-eclampsia. Other serum/plasma components related to the risk of pre-eclampsia were also measured. Between 12 and 35 weeks, whole-blood Se concentration increased significantly in the Se-treated group but decreased significantly in the placebo group. At 35 weeks, significantly higher concentrations of whole-blood Se and plasma SEPP1 were observed in the Se-treated group than in the placebo group. In line with our hypothesis, the concentration of sFlt-1 was significantly lower at 35 weeks in the Se-treated group than in the placebo group in participants in the lowest quartile of Se status at baseline (P= 0·039). None of the secondary outcome measures was significantly affected by treatment. The present finding that Se supplementation has the potential to reduce the risk of pre-eclampsia in pregnant women of low Se status needs to be validated in an adequately powered trial.

Macrophages: are they involved in endometriosis, abortion and preeclampsia and how?

Macrophages hold a key role in both regulating and executing the body's own immune response under various conditions. Hence, although endometriosis, preeclampsia and abortions are clinically different, all three are regarded to involve highly complex immunological processes. The aim of our current work was to evaluate the role of macrophages within these gynaecological disorders. Macrophages have been shown to invade endometriosis lesions and to mediate propagation of endometriotic cyst growth. However this is the first time that significant GPER up-regulation in macrophages is demonstrated. This highlights a potential alternative way through which estrogen may modulate immune response of macrophages in endometriosis. In addition, during spontaneous miscarriages the macrophage population increases significantly. This deregulation may possibly support an inflammatory scheme further triggering abortive procedures. Macrophage-mediated apoptosis of extravillous trophoblasts (EVT) has been associated with preeclampsia. Larger numbers of apoptotic EVT were detected in preeclamptic placentas compared with normal. In preeclamptic placentas, decidual macrophages were found to be Fas ligand (FasL)-positive. Our results highlight a new aspect of macrophage biology in endometriosis and pregnancy physiology and patho-physiology. Further studies with larger samples are needed to verify the current results and evaluate their clinical impact. Our data strongly indicate that macrophages hold key roles in various gynaecological disorders and might be crucial to further elucidate their patho-physiology.

Review: maternal and placental antioxidant response to preeclampsia - impact on vasoactive eicosanoids

The abnormally developed placenta is believed to be the pathophysiological cause of preeclampsia (PE). The resulting malperfusion of the placenta in PE can be associated with fluctuations in oxygen levels, leading to oxidative stress. How then do the placenta and the circulatory system of the mother adapt and respond to the increased oxidative challenge associated with PE? Many antioxidant systems have been shown to be upregulated or downregulated in the placenta and/or the maternal circulation during PE. Such altered antioxidant response can lead to increased lipid peroxidation. Oxidation of arachidonoyl residues in phospholipids generates bioactive lipids such as F2-isoprostanes, which are known vasoconstrictors. The consequences of changes in antioxidant status can also affect signal transduction and enzymatic pathways related to eicosanoid synthesis.

Effect of prenatal hypoxia in transgenic mouse models of preeclampsia and fetal growth restriction

Mice lacking endothelial nitric oxide synthase (eNOS(-)(/-)) or catechol-O-methyl transferase (COMT(-/-)) exhibit a preeclampsia-like phenotype and fetal growth restriction. We hypothesized that a hypoxic insult would result in a more severe phenotype. Pregnant eNOS(-/-), COMT(-/-) and control (C57BL/6J) mice were randomized to hypoxic (10.5% O(2)) or normal conditions (20.9% O(2)) from gestational day 10.5 to 18.5. Hypoxia increased the blood pressure in all genotypes and proteinuria in C57BL/6J and eNOS(-/-) mice. Fetal survival was significantly reduced following hypoxia, particularly in eNOS(-/-) mice. Birth weight was decreased in both C57BL/6J and COMT(-/-) mice. Placentas from COMT(-/-) mice demonstrated increased peroxynitrite. Despite similar hypoxia-induced effects on maternal blood pressure and proteinuria, eNOS(-/-) embryos have a decreased tolerance to hypoxia. Compared to C57BL/6J, COMT(-/-) mice exhibited less severe changes in proteinuria and fetal growth when exposed to prenatal hypoxia. This relative resistance to prenatal hypoxia was associated with a significant increase in placental levels of peroxynitrite.

Evolutionary perspectives into placental biology and disease

In all mammals including humans, development takes place within the protective environment of the maternal womb. Throughout gestation, nutrients and waste products are continuously exchanged between mother and fetus through the placenta. Despite the clear importance of the placenta to successful pregnancy and the health of both mother and offspring, relatively little is understood about the biology of the placenta and its role in pregnancy-related diseases. Given that pre- and peri-natal diseases involving the placenta affect millions of women and their newborns worldwide, there is an urgent need to understand placenta biology and development. Here, we suggest that the placenta is an organ under unique selective pressures that have driven its rapid diversification throughout mammalian evolution. The high divergence of the placenta complicates the use of non-human animal models and necessitates an evolutionary perspective when studying its biology and role in disease. We suggest that diversifying evolution of the placenta is primarily driven by intraspecies evolutionary conflict between mother and fetus, and that many pregnancy diseases are a consequence of this evolutionary force. Understanding how maternal-fetal conflict shapes both basic placental and reproductive biology - in all species - will provide key insights into diseases of pregnancy.

Elevated hyaluronan and extracellular matrix metalloproteinase inducer levels in women with preeclampsia

PURPOSE

Preeclampsia (PE) is a specific syndrome of pregnancy clinically identified by hypertension and proteinuria from the 20th week of gestation associated with a systemic inflammatory response and oxidative stress. While pro-inflammatory cytokines have been extensively studied in PE, other factors in the circulation that also influence the magnitude of inflammation have received much less attention. The present study compared serum concentrations of five immune-regulatory compounds in normotensive pregnant women and in women with gestational hypertension (GH) or PE.

METHODS

Sixty women with PE, 53 with GH and 40 normotensive women paired by gestational age were evaluated. Sera were evaluated for concentrations of extracellular matrix metalloproteinase inducer (EMMPRIN), hyaluronan, gelsolin, visfatin and histone 2B by ELISA. Differences between groups were analyzed by nonparametric tests, with a significance level of 5%.

RESULTS

Increased levels of EMMPRIN and hyaluronan were present in preeclamptic women as compared to the GH and normotensive groups. There was no difference between groups in gelsolin, visfatin or histone 2B.

CONCLUSION

Increased release of EMMPRIN and hyaluronan may contribute to an elevated pro-inflammatory response and tissue damage in women with PE.

Ischemia-modified albumin in pregnancy

OBJECTIVE

In normal pregnancies, a hypoxic intrauterine environment seems necessary for early trophoblast development. In this context, maternal serum levels of ischemia-modified albumin (IMA) are elevated, reflecting the oxidative stress associated with placental development. The aim of this study was to evaluate IMA and pregnancy-associated plasma protein A (PAPP-A) in mothers bearing small-for-gestational-age (SGA) fetuses compared to normal pregnancies.

STUDY DESIGN

A prospective study was performed between June 2010 and June 2011. Serum total albumin, IMA and PAPP-A concentrations were determined in 81 pregnant women in three different periods: 1st trimester, 2nd trimester and postpartum. Two groups of subjects were retrospectively identified: Group (1) mothers bearing appropriate-for-gestational-age (AGA) fetuses, and Group (2) mothers bearing SGA fetuses. Serum total albumin and IMA concentrations were determined in 198 non-pregnant women as controls.

RESULTS

Serum IMA concentrations increase during gestation. IMA/albumin serum levels in the 1st trimester were significantly higher in subjects of Group (2) (p<0.05), whereas values of serum PAPP-A MoM were significantly lower (p<0.05).

CONCLUSIONS

Elevated IMA serum levels together with low levels of PAPP-A were detected in the 1st trimester in mothers bearing SGA fetuses, and this may reflect early placental changes occurring before clinical manifestation of SGA.

The role of placental indoleamine 2,3-dioxygenase in human pregnancy

Munn et al. made a scientific observation of major biological importance. For the first time they showed that in the mammal the fetus does survive an immune attack mounted by the mother, and that the mechanism responsible for the survival depends on the fetus and placenta 'actively' defending itself from attack by maternal T cells by means of an enzyme indoleamine 2,3-dioxygenase (EC 1.13.11.42) dependent localised depletion of L-tryptophan. These findings raise critical questions for disease and its prevention during human pregnancy. Specifically, the role of this mechanism (discovered in mouse) in the human, and the extent to which defective activation of this process is responsible for major clinical diseases are unknown. Therefore some key facts about this enzyme expressed in the human placenta have been studied in order to test whether Munn et al.'s findings in mouse are met for human pregnancy. This short review attempts to describe our experimental work on human placental indoleamine 2,3-dioxygenase.

Placental Vacuolar ATPase Function Is a Key Link between Multiple Causes of Preeclampsia

Preeclampsia, a relatively common pregnancy disorder, is one of the major causes of maternal and fetal morbidity and mortality. Despite numerous research, the etiology of this syndrome remains not well understood as the pathogenesis of preeclampsia is complex, involving interaction between genetic, immunologic, and environmental factors. Preeclampsia, originating in placenta abnormalities, is induced by the circulating factors derived from the abnormal placenta. Recent work has identified various molecular mechanisms related to placenta development, including renin-angiotensin system, 1, 25-dihydroxyvitamin D, and lipoxin A4. Interestingly, advances suggest that vacuolar ATPase, a key molecule in placentation, is closely associated with them. Therefore, this intriguing molecule may represent an important link between various causes of preeclampsia. Here, we review that vacuolar ATPase works as a key link between multiple causes of preeclampsia and discuss the potential molecular mechanisms. The novel findings outlined in this review may provide promising explanations for the causation of preeclampsia and a rationale for future therapeutic interventions for this condition.

Association of microparticles and preeclampsia

Preeclampsia (PE) is a syndrome characterized by poor placentation and endothelial dysfunction. The diagnosis for this syndrome is based in hypertension and proteinuria presented after the 20th week of pregnancy. Despite intensive research, PE is still one of the leading causes of maternal mortality, although reliable screening tests or effective treatments of this disease have yet to be proposed. Microparticles (MPs) are small vesicles released after cell activation or apoptosis, which contain membrane proteins that are characteristic of the original parent cell. MPs have been proven to play key role in thrombosis, inflammation, and angiogenesis, as well as to mediate cell-cell communication by transferring mRNAs and microRNA from the cell of origin to target cells. Placenta-derived syncytiotrophoblast MPs are one of the most increased MPs during PE and may play an important role in the pathogenesis of this syndrome. Therefore, a better overall understanding of the role of MPs in PE may be useful for new clinical diagnoses and therapeutic approaches.

Expression of inflammatory cytokines in placentas from pregnancies complicated with preeclampsia and HELLP syndrome

OBJECTIVE

To investigate the expression of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and interleukin-10 (IL-10) in villous trophoblast, syncytial knots and decidua placentas from pregnancies complicated with preeclampsia (PE), Hemolysis, Elevated Liver enzymes and Low Platelet count (HELLP) syndrome and gestational age-matched controls.

METHODS

Study group included 35 placentas from pregnancies complicated with PE and 35 placentas from pregnancies with HELLP syndrome. Control group included 35 placentas from idiopathic preterm labor. Placentas were matched according to the gestational age. Expression of TNF-α, IL-6 and IL-10 was determined by immunohistochemistry and semi-quantitative HSCORE method in villous trophoblast, syncytial knots and decidua. Non-parametric statistics were used for analyses.

RESULTS

There was no difference in the expression of TNF-α, IL-6 and IL-10 in all the studied placental segments between PE, HELLP and gestational age-matched control group. TNF-α (F = 32, 41, p < 0.001), IL-6 (F = 58, 53, p < 0.001) and IL-10 (F = 17, 62, p < 0.001) expression was significantly different in different placental cell types, the highest expression of cytokines was in decidua.

CONCLUSION

There was no difference in cytokine expression in villous trophoblast, syncytial knots and decidua among the studied placental groups. The expression of cytokines was highest in decidua in all the studied placental groups.

Association of fetal-derived hypermethylated RASSF1A concentration in placenta-mediated pregnancy complications

OBJECTIVES

To assess whether fetal-derived hypermethylated RASSF1A concentrations in maternal plasma during pregnancy are altered in pregnancies associated with placental dysfunction manifested by intrauterine growth restriction (IUGR), preeclampsia (PE), or placental previa (PP) and whether this alteration can be detected in susceptible subjects before the onset of clinical disease.

METHODS

We performed a real-time quantitative polymerase chain reaction to quantify RASSF1A concentrations before and after methylation-sensitive restriction digestion in maternal plasma at 7-41 gestational weeks of normal pregnancies (n = 161), IUGR (n = 43), PE (n = 22), PP (n = 14) and non-pregnant women (n = 20).

RESULTS

A positive correlation was observed between fetal-derived hypermethylated RASSF1A concentration and gestational age for all study groups (r = 0.624, p < 0.001 for IUGR; r = 0.381, p = 0.042 for PE; r = 0.697, p < 0.001 for PP; r = 0.560, p < 0.001 for controls). The concentration of hypermethylated RASSF1A was relatively high at 7-14 gestational weeks in all patient groups. Hypermethylated RASSF1A concentration at 15-28 weeks was significantly higher in patients who subsequently developed IUGR (p = 0.002), PE (p < 0.001) or PP (p < 0.001) than in controls.

CONCLUSION

We first demonstrated increased concentration of fetal-derived hypermethylated RASSF1A sequences according to advancing gestation and before the onset of the clinical manifestation of pregnancy complications secondary to placental dysfunction, such as IUGR, PE and PP. Hypermethylated RASSF1A in maternal plasma may be useful as a potential biomarker to detect placental-mediated pregnancy complications, regardless of fetal gender and polymorphism.