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Excess syncytiotrophoblast microparticle shedding is a feature of early-onset pre-eclampsia, but not normotensive intrauterine growth restriction
Abstract
Syncytiotrophoblast microparticles (STBM) are shed into the maternal circulation in higher amounts in pre-eclampsia compared to normal pregnancy and are believed to be the stimulus for the systemic inflammatory response and endothelial cell damage which characterises the maternal syndrome. The excess shedding of STBM may be caused by hypoxia as a result of poor placentation, which is often a feature of pre-eclampsia. Similar placental pathology occurs in some cases of normotensive intrauterine growth restriction (nIUGR), but in the absence of maternal disease.
To examine whether the shedding of STBM in nIUGR occurs to the same extent as in pre-eclampsia.
A prospective case-control study in a tertiary referral centre of: 1) women with early-onset pre-eclampsia (EOPET < 34 week), 2) women with late-onset pre-eclampsia (LOPET > or = 34 week), 3) women with nIUGR), 4) matched normal pregnant women (NPC), and 5) non-pregnant women. An ELISA using the antitrophoblast antibody NDOG2 was used to measure STBM levels in peripheral venous plasma. Non-parametric analyses were conducted with statistical significance set at p < 0.05.
STBM levels rise during normal pregnancy. EOPET was associated with increased STBM levels (EOPET (median): 41 ng/ml, n = 15) compared with matched normal pregnancy (16 ng/ml, n = 15; Wilcoxon p = 0.005). LOPET (50 ng/ml, n = 10) and nIUGR (18 ng/ml, n = 8) STBM levels did not differ from matched normal pregnancy (36 ng/ml, n = 15, and 36 ng/ml, n = 8, respectively). Background levels in non-pregnant plasma were 0.49 ng/ml, n = 10.
Increased STBM levels were found in EOPET but not in nIUGR providing further evidence for their role in the pathogenesis of the maternal syndrome.
... It was hypothesized that a rise in adipose tissue may cause an inflammatory response, disrupting growth, and placental angiogenesis, ultimately resulting in PE [12]. Endothelial dysfunction and oxidative stress are significant contributors to the pathogenesis of preeclampsia by inducing the excessive production of pro-inflammatory mediators throughout the body [13,14]. It can be said that PE may be associated with inflammation, which may be induced by an infection as well [15]. ...
... Several mechanisms have been proposed to be implicated in probiotics' potential blood pressure-reducing effects. These mechanisms include the potential to decrease systemic inflammation [13,14], and oxidative stress [39], as well as to stabilize the renin-angiotensin system and subsequently contribute to blood pressure regulation [40]. Furthermore, probiotics have been suggested to have a role to lower total cholesterol and lowdensity lipoprotein (LDL) levels [36,41], reducing blood sugar, and modulating insulin resistance [42]. ...
... Evidence indicates that excessive inflammatory responses may have a significant impact on the development of PE [58]. Thus, endothelial dysfunction induced by oxidative stress and systemic inflammation are crucial determinants of PE [13,14]. Furthermore, an increase in oxidative stress during pregnancy was associated with various unfavorable outcomes, including PE [39], low birth weight [59], preterm delivery [60], and thrombocytopenia [61]. ...
Introduction
Preeclampsia affects a significant percentage of pregnancies which is a leading cause of premature birth. Probiotics have the potential to affect inflammatory factors, and oxidative stress, which are linked to the development of preeclampsia. The study aimed to compare the effect of synbiotic and placebo on blood pressure and pregnancy duration as primary outcomes, and other pregnancy outcomes.
Methods
This study comprised 128 pregnant women with mild preeclampsia and gestational ages exceeding 24 weeks who were referred to the high-risk pregnancy clinic. It was a randomized, controlled, phase III, triple-blinded clinical experiment. The intervention and control groups were distributed to the participants at random. Intervention group received one oral synbiotic capsule, and control group received placebo daily until delivery. Based on gestational age at the time of diagnosis, preeclampsia was stratificated as early (< 34 weeks) or late (≥ 34 weeks). Data obtained from questionnaires, and biochemical serum factors were analyzed using SPSS software version 23 software.
Results
With the exception of the history of taking vitamin D3, there were no statistically significant variations in socio-demographic variables between the research groups. After the intervention, the means of systolic blood pressure (adjusted mean difference: -13.54, 95% CI: -5.01 to -22.07), and diastolic blood pressure (adjusted mean difference: -10.30, 95% CI: -4.70 to -15.90) were significantly lower in the synbiotic-supplemented group than in the placebo group. Compared to the placebo group, the incidence of severe PE (p < 0.001), proteinuria (p = 0.044), and mean serum creatinine level (p = 0.005) significantly declined in the synbiotic-supplemented group after the intervention. However, our analysis found no significant association for other outcomes.
Conclusion
Based on our results, synbiotic had beneficial effects on some pregnancy outcomes. Further studies with larger samples are needed to verify the advantages of synbiotic supplementation for high-risk pregnancies, particularly with regards to higher doses, and longer intervention periods.
Trial registration
IRCT20110606006709N20.
... The dynamic release of sEVs in reaction to maternal organ dysfunction, along with the stability of sEVs and their cargo within biological fluids such as plasma, has brought attention to utilizing noninvasive liquid biopsies and sEV characterization for diagnosing or monitoring the progression of pregnancy-related disorders including PE [37,53,80,88,90]. Specific sEV subpopulations, such as PLAP + syncytiotrophoblastderived microparticles (STBMs) and CD68 + exosomes, have been reported to be elevated in PE patient plasma [23,53,86,[96][97][98][99][100]. However, isolating and quantifying sEV subpopulations is often labor-and time-intensive making it difficult to implement in a clinical setting. ...
... LOPE patients generally have normal placentation, but excessive fetal metabolic demand late in the third trimester is thought to overwhelm the functional capacity of the placenta and cause placental cell stress without evidence of abnormal maternal perfusion [15,23,93]. In contrast, abnormal placentation and reduced perfusion due to compromised placental oxygen signaling are thought to contribute to the pathogenesis that primarily characterizes early onset PE phenotypes [19,22,30,55,93,96]. Shallow decidual invasion and incomplete spiral artery remodeling are key pathogenic features underlying EOPE, and EOPE placentas commonly exhibit signs of oxidative placental cell stress [10,15,22,25,27,28,30,62]. ...
Preeclampsia (PE) is a leading cause of maternal and fetal mortality and morbidity. While placental dysfunction is a core underlying issue, the pathogenesis of this disorder is thought to differ between early-onset (EOPE) and late-onset (LOPE) subtypes. As recent reports suggest that small extracellular vesicles (sEVs) contribute to the development of PE, we have compared systemic sEV concentrations between normotensive, EOPE, and LOPE pregnancies. To circumvent lengthy isolation techniques and intermediate filtration steps, a streamlined approach was developed to evaluate circulating plasma sEVs from maternal plasma. Polymer-based precipitation and purification were used to isolate total systemic circulating maternal sEVs, free from bias toward specific surface marker expression or extensive subpurification. Immediate Nanoparticle Tracking Analysis (NTA) of freshly isolated sEV samples afforded a comprehensive analysis that can be completed within hours, avoiding confounding freeze–thaw effects of particle aggregation and degradation.
Rather than exosomal subpopulations, our findings indicate a significant elevation in the total number of circulating maternal sEVs in patients with EOPE. This streamlined approach also preserves sEV-bound protein and microRNA (miRNA) that can be used for potential biomarker analysis. This study is one of the first to demonstrate that maternal plasma sEVs harbor full-length hypoxia inducible factor 1 alpha (HIF-1α) protein, with EOPE sEVs carrying higher levels of HIF-1α compared to control sEVs. The detection of HIF-1α and its direct signaling partner microRNA-210 (miR-210) within systemic maternal sEVs lays the groundwork for identifying how sEV signaling contributes to the development of preeclampsia. When taken together, our quantitative and qualitative results provide compelling evidence to support the translational potential of streamlined sEV analysis for future use in the clinical management of patients with EOPE.
... Although the embryo or fetus can also contribute EVs that pass through the placental barrier into the maternal circulation [15,16], most of the fetal-derived EVs in the maternal circulation are derived from placental trophoblasts. Placental EVs can be seen in the maternal circulation, identified by the placental-type alkaline phosphate (PLAP) marker, from as early as 6 weeks of gestation [17], with numbers increasing throughout pregnancy [18][19][20]. ...
... Placental small-EVs encompass exosomes that originate from the late endosomal system [4], but also nano-sized EVs that originate through other routes of biogenesis, e.g. through blebbing at the surface membrane of the syncytiotrophoblast. The concentrations of both large-and small-EVs collected from placental explants increase substantially (∼100-fold) from 8 to 12 weeks of gestation [18], while up to ∼8-fold increase in concentrations have been reported in the maternal blood from first-trimester to third-trimester [19,20]. ...
Human pregnancy is a highly orchestrated process requiring extensive cross-talk between the mother and the fetus. Extracellular vesicles released by the fetal tissue, particularly the placenta, are recognized as important mediators of this process. More recently, the importance of placental extracellular vesicle biodistribution studies in animal models has received increasing attention as identifying the organs to which extracellular vesicles are targeted to helps us understand more about this communication system. Placental extracellular vesicles are categorized based on their size into macro-, large-, and small-extracellular vesicles, and their biodistribution is dependent on the extracellular vesicle's particle size, the direction of blood flow, the recirculation of blood, as well as the retention capacity in organs. Macro-extracellular vesicles are exclusively localized to the lungs, while large- and small-extracellular vesicles show high levels of distribution to the lungs and liver, while there is inconsistency in the reporting of distribution to the spleen and kidneys. This inconsistency may be due to the differences in the methodologies employed between studies and their limitations. Future studies should incorporate analysis of placental extracellular vesicle biodistribution at the macroscopic level on whole animals and organs/tissues, as well as the microscopic cellular level.
... We further demonstrated that NRP-1 is co-expressed on PLAP positive vesicles. STB-EVs are reportedly shed in the circulation from 1st trimester of pregnancy till term [48]. They are also found in vastly increased amounts of STB-EVs in the circulation of PE women compared to NP [48]. ...
... STB-EVs are reportedly shed in the circulation from 1st trimester of pregnancy till term [48]. They are also found in vastly increased amounts of STB-EVs in the circulation of PE women compared to NP [48]. Even though the expression levels of NRP-1 were not substantially different, the absolute circulating PLAP þ ve STB-EV levels are higher in PE and may also translate to higher circulating PLAP þ ve NRP-1 þve STB-EV where it is likely that they could target endothelial cells and probably forming an active complex with VEGFR-2. ...
Preeclampsia (PE) is a multisystem progressive hypertensive disorder unique to human pregnancy. The placenta is fundamental to its pathogenesis and releases placental factors as well as extracellular vesicles (small and medium/large syncytiotrophoblast extracellular vesicles (STB-EVs)) as a response to syncytiotrophoblast stress such as tissue factor and plasminogen activator inhibitors 1. Neuropilin 1 (NRP-1) is an anti-angiogenic factor involved in development, angiogenesis, arteriogenesis, and vascular permeability. NRP-1 acts as a co-receptor for growth factors such as vascular endothelial growth factor (VEGF), placenta growth factor (PLGF), and epidermal growth factor (EGF). Given the documented pro and anti-angiogenic roles of STB-EVs, we hypothesized that 1) STB-EVs might express NRP-1; and 2) the expression of NRP-1 might differ between normal and preeclampsia STB-EVs.
Methods:
We isolated STB-EVs (both small and medium/large) from PE and NP placentae using the physiologic ex vivo dual lobe perfusion model. The enriched STB-EVs were characterized by Western blot, transmission electron microscopy (TEM), and nanoparticle tracking analysis (NTA) according to the international society of extracellular vesicles (ISEV) guidelines. We assessed for NRP-1 expression with Western blot (placenta and STB-EVs) and immunohistochemistry (placenta). We performed co-expression analysis for placenta alkaline phosphatase (PLAP - a known STB-EV marker) and NRP-1 with immunoprecipitation followed by Western blot.
Results:
We confirmed NRP-1 expression in NP and PE placenta. We showed that NRP-1 Expression was limited to small syncytiotrophoblast membrane extracellular vesicles (S STB-EVs) but not medium/large STB-EVs and that NRP-1 is co-expressed with PLAP.
Conclusion:
Neuropilin-1 is uniquely expressed on small syncytiotrophoblast extracellular vesicles but not on medium/large vesicles from preeclampsia and normal placentae.
... Any pregnant woman experiencing a convulsion in an emergency setting is presumed to have eclampsia unless proven otherwise, given the association with visual disturbances, as suggested by the Greek meaning of eclampsia 9,31 . The condition is characterized by generalized convulsions and/or coma in the setting of pre-eclampsia and without other neurologic conditions 10,55 . ...
Pre-eclampsia remains a significant cause of maternal and fetal morbidity and mortality worldwide 4. This hypertensive disorder of pregnancy poses challenges in both diagnosis and management, requiring a multidisciplinary approach for optimal care. Early recognition of pre-eclampsia, along with vigilant antenatal surveillance, is crucial for timely intervention and prevention of complications. Management strategies focus on blood pressure control, seizure prophylaxis, and careful monitoring of maternal and fetal well-being. Regional anesthesia is often preferred for cesarean section to avoid the hypertensive response associated with general anesthesia 7,32. In the ICU setting, close monitoring and prompt intervention are essential to manage complications such as pulmonary edema and thromboembolism 3,12. Postpartum care involves continued monitoring for complications and appropriate thromboprophylaxis. Overall, a systematic and coordinated approach to the management of pre-eclampsia is essential for improving outcomes for both mother and baby.
... The syncytiotrophoblast layer of the placenta releases EVs (STB-EVs) into the maternal circulation from early first trimester and the amount of EV release increases as the pregnancy advances 33 . Preeclamptic placenta is known to release more STB-EVs compared to normal pregnancy 34 . STB-EVs in preeclampsia have been shown to regulate distant cells (such as endothelial cells) by depositing the contents of their cargoes causing vascular dysfunction, platelet activation, vasoconstriction, and endothelial activation [35][36][37][38] . ...
Preeclampsia (PE) is a hypertensive disorder in pregnancy affecting 2-8% of pregnancies worldwide and remains one of the leading causes of maternal and neonatal morbidity and mortality. PE is characterized by hypertension and end-organ damage secondary to oxidative stress, endothelial dysfunction, and vasoconstriction. The pathophysiology of the disease being elusive, early screening, diagnosis, and effective management of PE is challenging. Traditionally several predictive models including clinical and biochemical parameters have been used to stratify the risk of developing PE in pregnancy. Poor sensitivity and specificity of these models have been a limitation and has inspired the clinical world to explore more tools to screen and diagnose PE prior to the onset of clinical syndrome. This review attempts to highlight the recent developments in the newly developed screening tools and explores the future direction of preeclampsia screening research.
... Multiple evidence suggests that preeclampsia and gestational hypertension have various demonstrations, including vascular changes, vasospasm, and disorders in body systems due to maternal vascular endothelium pathology (10). Among the pathogens proposed for preeclampsia, endothelial disorder and inflammatory response are an important part of the pathogenesis of preeclampsia, which can also be caused by oxidative 14 stress (11,12). Evidence shows that maternal excessive inflammatory response is responsible for preeclampsia (13). ...
Objectives: Background: Preeclampsia is one of the main causes of premature birth, growth restriction, and intrauterine death of fetus. Probiotics has the potential to modulate inflammatory and oxidative stress biomarkers that implicated in the pathophysiology of preeclampsia. The aim of the present study is to establish the impact of synbiotic supplements, comprising of probiotic and prebiotic fructooligosaccharide, in comparison to placebo, on the maternal and neonatal outcome outcomes in women afflicted with mild preeclampsia. Methods: This is a study protocol of a randomized, controlled, phase 3, triple-blind, randomized clinical trial. The classification is based on the gestational age at the time of diagnosis of mild preeclampsia (early-onset or late-onset preeclampsia). Participants will be 128 pregnant women with mild pre-eclampsia (systolic blood pressure between 140-160 mm Hg or diastolic blood pressure between 90-110 mm Hg, along with other preeclampsia symptoms). Participants will divide into two intervention and control groups using a 1:1 random allocation ratio randomly. They will receive one oral capsule (the concentration of 109 CFU) or placebo daily from admission until delivery. Primary outcomes included mean systolic and diastolic blood pressure, mean gestational age from diagnosis to delivery, and mean birth weight. Also, secondary outcomes included proteinuria, serum creatinine level, the incidence of severe PE, the use of antihypertensive drugs, the rate of natural delivery, incidence of serious complications, maternal blood factors such as platelet count, and serum levels of liver enzymes such as ALT, AST, bilirubin, and LDH. Discussion: The present trial can importantly contribute to the selection of an appropriate Synbiotic supplement as safe pharmaceutical adjuvants in the treatment of pregnant women with mild preeclampsia and prevention of maternal and neonatal complications. Trial Registration: IRCT20110606006709N20. Registered on August 13, 2022.
... Shedding of the syncytiotrophoblast-derived microparticles (STBM; size range: 20 to 3000 nm) in the maternal circulation increased significantly in PE compared to healthy controls 52 . Circulating exosomes are also reported to increase in pre-eclamptic women and contain altered molecular cargo making them pro-inflammatory, anti-angiogenic and pro-coagulant, thereby generating maternal systemic inflammation, endothelial vascular dysfunction and clotting system activation, the defining features of PE 53 . ...
Pre-eclampsia (PE), a multifactorial de novo hypertensive pregnancy disorder, is one of the leading causes of foeto-maternal morbidity and mortality. Currently, antihypertensive drugs are the first-line therapy for PE and evidence suggests that low-dose aspirin initiated early in high risk pregnancies may reduce the risk of development or severity of PE. However, an early prediction of this disorder remains an unmet clinical challenge. Several potential serum biomarkers associated with maternal immunoregulation and placental angiogenesis have been evaluated but are ineffective and inconsistent for early prediction. Although placental biomarkers would be more specific and sensitive in predicting the risk of PE, accessing the placenta during pregnancy is not feasible. Circulating placental exosomes (pEXO), originating from foeto-maternal interface, are being evaluated as the placenta's surrogate and the best source of non-invasive placental biomarkers. pEXO appear in the maternal circulation starting from six weeks of gestation and its dynamic biological cargo across pregnancy is associated with successful pregnancy outcomes. Therefore, monitoring changes in pEXO expression profiles could provide new insights into the prediction, diagnosis and treatment of PE. This narrative review comprehensively summarizes the available literature on the candidate predictive circulating biomarkers evaluated for PE to date. In particular, the review elucidates the current knowledge of distinct molecular signatures emanating from pEXO in pre-eclamptic women to support the discovery of novel early predictive biomarkers for effective intervention and management of the disease.
... EVs are based on size into medium/large STB-EVs (MVs, 201-1000nm) or small STB-EVs (≤200nm) (Dragovic et al., 2015b ). The release of syncytiotrophoblast extracellular vesicles (STB-EVs) into the maternal circulation increases with gestation and is further elevated in PE. (Germain et al., 2007 ;Goswamia et al., 2006 ) The presence of proteins, RNA species and DNA in EVs combined with their constitutional release as inter-cellular signaling moieties means they also have potential in disease prediction and diagnosis. In this study, we performed proteomic analysis of placenta and STB-EVs in PE and NP to identify potential placenta-derived biomarkers. ...
Preeclampsia (PE), a multi-systemic hypertensive pregnancy disease that affects 2-8% of pregnancies worldwide, is a leading cause of adverse maternal and fetal outcomes. Current clinical PE tests have a low positive predictive value for PE prediction and diagnosis. The placenta notably releases extracellular vesicles from the syncytiotrophoblast (STB-EV) into the maternal circulation.
To identify a difference in placenta and STB-EV proteome between PE and normal pregnancy (NP), which could lead to identifying potential biomarkers and mechanistic insights.
Using ex-vivo dual lobe perfusion, we performed mass spectrometry on placental tissue, medium/large and small STB-EVs isolated from PE (n = 6) and NP (n = 6) placentae. Bioinformatically, mass spectrometry was used to identify differentially carried proteins. Western blot was used to validate the identified biomarkers. We finished our investigation with an in-silico prediction of STB-EV mechanistic pathways.
We identified a difference in the STB-EVs proteome between PE and NP. Filamin B, collagen 17A1, pappalysin-A2, and scavenger Receptor Class B Type 1) were discovered and verified to have different abundances in PE compared to NP. In silico mechanistic prediction revealed novel mechanistic processes (such as abnormal protein metabolism) that may contribute to the clinical and pathological manifestations of PE.
We identified potentially mechanistic pathways and identified differentially carried proteins that may be important in the pathophysiology of PE and are worth investigating because they could be used in future studies of disease mechanisms and as biomarkers.
This research was funded by the Medical Research Council (MRC Programme Grant (MR/J0033601) and the Medical & Life Sciences translational fund (BRR00142 HE01.01)
... 54) Therefore, Pl-exosomes may be involved in the pathogenesis of PE by disrupting immune tolerance and impairing remodeling of spiral arteries. Numbers of STB-derived EVs (including exosomes) are higher in PE than in normal maternal blood, 55) and even higher in earlyonset PE. 56) The excessive discharge of STBMs in PE is thought to be caused by hypoxia due to placentation failure, a characteristic feature of the disease. STBMs released toward the intervillous space will flow directly into the maternal blood. ...
Preeclampsia is a pregnancy-related complication caused by impaired remodeling of the spiral artery in association with inappropriate implantation. A maladaptive immune response in early- to mid-pregnancy is thought to allow impaired angiogenesis that leads to poor placentation. Furthermore, poor placentation can lead to maternal systemic organ damage via increased placenta-derived humoral factors including anti-angiogenic factors and proinflammatory cytokines. Exosomes are cell-derived vesicles with a diameter of 50–100 nm. They contain micro-RNAs, DNA, and proteins that can affect both local and distant tissues. Exosomes derived from syncytiotrophoblasts might promote the pathogenesis of preeclampsia, and conversely, exosomes derived from mesenchymal stem cells might ameliorate the condition. Further studies focusing on exosomes are expected to clarify the pathogenesis of preeclampsia and lead to the development of new predictive tools and treatments for preeclampsia.
... Generally, total exosome count and placental-specific exosome count are both increased under most pathological conditions. 52,62,63 During pregnancy, there is a significant increase in the concentration of total exosomes and placental exosomes in maternal plasma of presymptomatic women who later develop PE. 64,65 Previous reports have demonstrated that the placenta responds to changes in tension by releasing more exosomes, affecting both content and bioactivity on cell targets. 66 In particular, exosomes from trophoblast cells cultured at 8% oxygen have been found to increase the level of endothelial cell migration. ...
Serving as the interface between fetal and maternal circulation, the placenta plays a critical role in fetal growth and development. Placental exosomes are small membrane-bound extracellular vesicles released by the placenta during pregnancy. They contain a variety of biomolecules, including lipids, proteins, and nucleic acids, which can potentially be biomarkers of maternal diseases. An increasing number of studies have demonstrated the utility of placental exosomes for the diagnosis and monitoring of pathological conditions such as pre-eclampsia and gestational diabetes. This suggests that placental exosomes may serve as new biomarkers in liquid biopsy analysis. This review provides an overview of the current understanding of the biological function of placental exosomes and their potential as biomarkers of maternal diseases. Additionally, this review highlights current barriers and the way forward for standardization and validation of known techniques for exosome isolation, characterization, and detection. Finally, microfluidic devices for exosome research are discussed.
... They reported that sSTB-EV levels fell rapidly postpartum (within 2 days), although this study purported to investigate EVs with very high PLAP levels which may have been large STB fragments [56,57]. m/lSTB-EVs have been reported in the circulation with elevated levels solely in the presence of EOPE and not in LOPE or gestation matched IUGR (intrauterine growth restriction) [58]. They demonstrated significant elevation of PLAP+ m/l STB-EVs above non-pregnant patients in all conditions. ...
Preeclampsia (PE) is a hypertensive complication of pregnancy that affects 2–8% of women worldwide and is one of the leading causes of maternal deaths and premature birth. PE can occur early in pregnancy (<34 weeks gestation) or late in pregnancy (>34 weeks gestation). Whilst the placenta is clearly implicated in early onset PE (EOPE), late onset PE (LOPE) is less clear with some believing the disease is entirely maternal whilst others believe that there is an interplay between maternal systems and the placenta. In both types of PE, the syncytiotrophoblast (STB), the layer of the placenta in direct contact with maternal blood, is stressed. In EOPE, the STB is oxidatively stressed in early pregnancy (leading to PE later in gestation- the two-stage model) whilst in LOPE the STB is stressed because of villous overcrowding and senescence later in pregnancy. It is this stress that perturbs maternal systems leading to the clinical manifestations of PE. Whilst some of the molecular species driving this stress have been identified, none completely explain the multisystem nature of PE. Syncytiotrophoblast membrane vesicles (STB-EVs) are a potential contributor to this multisystem disorder. STB-EVs are released into the maternal circulation in increasing amounts with advancing gestational age, and this release is further exacerbated with stress. There are good in vitro evidence that STB-EVs are taken up by macrophages and liver cells with additional evidence supporting endothelial cell uptake. STB-EV targeting remains in the early stages of discovery.
In this review, we highlight the role of STB-EVs in PE. In relation to current research, we discuss different protocols for ex vivo isolation of STB-EVs, as well as specific issues involving tissue preparation, isolation (some of which may be unique to STB-EVs), and methods for their analysis. We suggest potential solutions for these challenges.
... Additionally, different studies have shown that there are differences between EO-PE and LO-PE, as the number of placental microvesicles and pEXOs is higher in EO-PE compared to LO-PE. However, some studies have described that there are not changes in the levels of PLAP + EV between normotensive and LO-PE women, confirming the etiopathogenic differences between EO-PE and LO-PE (Goswamia et al., 2006;Orozco et al., 2009;Chen et al., 2012;Pillay et al., 2016). Regarding their content, lipidomic analysis have revealed that STBMs from PE women display enhanced levels of total phosphatidylserine whereas phosphatidylinositol, phosphatidic acid, and ganglioside mannoside 3 were significantly downregulated in comparison with normal pregnancies (Baig et al., 2013). ...
The human placenta is a critical structure with multiple roles in pregnancy, including fetal nutrition and support, immunological, mechanical and chemical barrier as well as an endocrine activity. Besides, a growing body of evidence highlight the relevance of this organ on the maternofetal wellbeing not only during gestation, but also from birth onwards. Extracellular vesicles (EVs) are complex macromolecular structures of different size and content, acting as carriers of a diverse set of molecules and information from donor to recipient cells. Since its early development, the production and function of placental-derived EVs are essential to ensure an adequate progress of pregnancy. In turn, the fetus receives and produce their own EVs, highlighting the importance of these components in the maternofetal communication. Moreover, several studies have shown the clinical relevance of EVs in different obstetric pathologies such as preeclampsia, infectious diseases or gestational diabetes, among others, suggesting that they could be used as pathophysiological biomarkers of these diseases. Overall, the aim of this article is to present an updated review of the published basic and translational knowledge focusing on the role of placental-derived EVs in normal and pathological pregnancies. We suggest as well future lines of research to take in this novel and promising field.
... The histopathological examination of pre-eclampsia placentas revealed: abnormal remodeling of maternal spiral arteries; acute atherosclerosis with fibrin necrosis; and accumulation of lipid-laden intimal macrophages. In addition, the syncytiotrophoblast hyperplasia with degeneration or apoptosis can lead to the release of trophoblast debris, cell-free DNA, exosomes, pro-inflammatory factors and anti-angiogenic factors for the circulation of a pregnant woman [22]. Most of the theories in the literature emphasize the importance of the vascular factor that is related to the placental vasoconstriction or damage to the endovascular endothelium [18,19]. ...
Pre-eclampsia is a placenta-related complication occurring in 2–10% of all pregnancies. miRNAs are a group of non-coding RNAs regulating gene expression. There is evidence that C19MC miRNAs are involved in the development of the placenta. Deregulation of chromosome 19 microRNA cluster (C19MC) miRNAs expression leads to impaired cell differentiation, abnormal trophoblast invasion and pathological angiogenesis, which can lead to the development of pre-eclampsia. Information was obtained through a review of articles available in PubMed Medline. Articles on the role of the C19MC miRNA in the development of pre-eclampsia published in 2009–2022 were analyzed. This review article summarizes the current data on the role of the C19MC miRNA in the development of pre-eclampsia. They indicate a significant increase in the expression of most C19MC miRNAs in placental tissue and a high level of circulating fractions in serum and plasma, both in the first and/or third trimester in women with PE. Only for miR-525-5p, low levels of plasma expression were noted in the first trimester, and in the placenta in the third trimester. The search for molecular factors indicating the development of pre-eclampsia before the onset of clinical symptoms seems to be a promising diagnostic route. Identifying women at risk of developing pre-eclampsia at the pre-symptomatic stage would avoid serious complications in both mothers and fetuses. We believe that miRNAs belonging to cluster C19MC could be promising biomarkers of pre-eclampsia development.
... [33][34][35] Inflammatory response onset during the first twelve weeks could be given by interactions occurring between the decidual immune cells and trophoblast cells, then in the second and third trimester, a secondary inflammatory response could be due to syncytiotrophoblast microparticles that are released into the mother´s vascular system and are detectable in maternal circulation. [36] Thus, two stages of the PE are proposed: poor trophoblastic invasion, given by altered production of immunoregulatory cytokines and angiogenic factors and a systemic, maternal-inflammatory response, primarily involving the endothelium, which is stimulated by the liberation of necrotic/apoptotic syncytiotrophoblast cells into the maternal circulation. [37] This second stage of could be involved in poor fetal growth and can be linked with the development of intrauterine growth restriction. ...
Background:
Preeclampsia (PE) is a syndromic disorder that affects 2% to 8% of pregnancies and is diagnosed principally when hypertension appears in the second-d half of pregnancy. WHO estimates the incidence of PE to be seven times higher in developing countries than in developed countries. Severe preeclampsia/eclampsia is one of the most important causes of maternal mortality, associated with 50,000 to 100,000 annual deaths globally as well as serious fetal and neonatal morbidity and mortality, especially in developing countries. Even though evidence from family-based studies suggest PE has a heritable component, its etiology, and specific genetic contributions remain unclear. Many studies examining the genetic factors contributing to PE have been conducted, most of them are focused on single nucleotide polymorphisms (SNPs). Given that PE has a very important inflammatory component, is mandatory to examine cytokine-SNPs for elucidating all mechanisms involved in this pathology. In this review, we describe the most important cytokine-polymorphisms associated with the onset and development of PE. We aim to provide current and relevant evidence in this regard.
Methods:
We searched English databases such as PubMed and the National Center for Biotechnology Information. The publication time of the papers was set from the establishment of the databases to February 2022. All studies about Th1/Th2/Th17 cytokines polymorphisms were included in our study.
Results:
SNPs in IFN-γ, TNF-α, IL-4, IL-6, IL-10, IL-17A, and IL-22 are associated with the development, early-onset and severity of PE, being the Th1/Th2/Th17 responses affected by the presence of these SNPs.
Conclusions:
The changes in Th1/Th2/Th17 response modify processes such as placentation, control of inflammation, and vascular function. Nonetheless, association studies have shown different results depending on sample size, diagnostic, and population.
... There are two potential explanations for STB-EV generation. The less talked about pathway is the alternate pathway ( However, the primary biogenetic mechanism (Figure 3), the classic pathway, results in the production of STB-EVs from activated syncytiotrophoblast cells or apoptotic syncytiotrophoblast cells 80,81 . This includes the production of small STB-EVs (including exosomes), medium/large STB-EVs (including microvesicles) or other extracellular vesicles ...
Introduction: Preeclampsia is a complication of pregnancy that affects 2-8 % of women worldwide. It is one of the leading causes of maternal deaths and premature birth. It is diagnosed by elevated blood pressure (≥ 140/90 mmHg), proteinuria, and/or end-organ damage. Although the precise mechanisms are not fully elucidated, the placenta is involved in this disease process. However, one theory is the role of extracellular vesicles STB-EVs, which are membrane-bound biomolecules that range between 30-1000 nm in size released by the placenta and detected in the circulation. STB-EVs have been reported to be higher in the circulation in PE compared to Normal pregnancy. In addition, the phenotype of the STB-EVs is believed to be different in PE compared to NP. However, it is unclear if the clinical manifestations attributable to STB-EVs in PE are a) because PE STB-EVs are more abundant in circulation, b) because they are of a different phenotype (bigger with a different cargo), or c) a combination of both. This thesis builds on the second premise.
Aim: My work explores the possibility that STB-EVs can act as biomarkers and mechanistic and therapeutic targets in PE.
Methodology: I have isolated and characterised STB-EVs from the placenta of 8 PE and 6 NP patients via ex vivo dual lobe placenta perfusion. I subjected these materials through mass spectrometry, coding RNA, small RNA sequencing, and multi-omics (transcriptomics, proteomics, and integrated multi-omics) data analysis. This is the first study of its kind in the field.
Results: My analysis identified a difference in STB-EV cargoes' transcriptomic and proteomic profiles between preeclampsia (PE) and normal pregnancy (NP). I then identified and verified the differential expression of transcripts (FLNB, COL17A1, SLC45A4, LEP, HTRA4, PAPP A2, EBI3, HSD17B1, FSTL3, INHBA, SIGLEC6, and CGB3), microRNA (hsa-miR-193b-5p, hsa-miR-324-5p, hsa-miR-652-3p, hsa-miR-3196, hsa-miR-9-5p, hsa-miR-421, and hsa-miR 210-3p in the Medium/large STB-EVs) and proteins (FLNB (filamin B), COL17A1 (Collagen 17A1), PAPP-A2 (Pappalysin-A2), and SR-BI (Scavenger Receptor Class B Type 1)) for potential use as biomarkers in preeclampsia.
My analysis also identified 1) interesting mechanistic processes such as abnormal protein metabolism, which may be responsible for the clinical and pathological presentation of preeclamptic patients, and 2) molecular clusters that may explain variations in the presentation of PE and potential therapeutic candidates (ceforamide, thiamine, dexibuprofen)
Conclusions: I performed comprehensive profiling of the transcriptome, proteome, and pathways in PE by analysing my three different sample subtypes (placenta, M/L STB-EVs, and S STB-EVs). I identified differentially expressed biomolecules (proteins and RNAs) and uncovered mechanistic pathways which may be important in the pathophysiology of PE and could potentially be used in future studies of disease mechanisms and as biomarkers.
Access here: https://ora.ox.ac.uk/objects/uuid:04df379b-12fc-4894-903f-d394bcc84357
... In addition, an overgrowth of syncytiotrophoblasts with degeneration or apoptosis of some of them has been observed. This leads to the release of trophoblastic debris [24], cell-free DNA [25], exosome, proinflammatory factors [26] and anti-angiogenic factors into the systemic circulation of pregnant women. At the molecular level, during oxidative stress, the activation of hypoxia-dependent gene expression regulation mechanisms in trophoblast cells was observed. ...
MicroRNAs (miRNAs) are a class of small non-coding, single-stranded RNAs (ribonucleic acids) that play important roles in many vital processes through their impact on gene expression. One such miRNA, miR210, represents a hypoxia-induced cellular miRNA group that hold a variety of functions. This review article highlights the importance of miR-210 in the development of pre-eclampsia.
• KEY MESSAGE
• miR-210 is a promising biomarker for monitoring pregnancy with pre-eclampsia. Overexpression of miR-210 had a negative impact on the process of cell migration and trophoblast invasion.
... Thus, early diagnosis and treatment of severe preeclampsia are essential for fetus maturation and prevention of seizure development. Preeclampsia and severe Preeclampsia induce the up-regulation of trophoblast fragments, indicating the induction of apoptosis in maternal turnover [27]. Accordingly, a probable correlation of trophoblast with apoptosis can modify the maternal bloodstream, and therefore causes the death of ACs in the pregnant woman that leads to adverse effects like preeclampsia. ...
Efferocytosis is the process by which apoptotic cells are removed without inflammation to maintain tissue homeostasis, prevent unwanted inflammatory responses, and inhibit autoimmune responses. Coordination of efferocytosis occurs via many surfaces and chemotactic molecules and adaptors. Recently, soluble positive or negative mediators of efferocytosis, have been more noticeable as non-invasive valuable biomarkers in prognosis and targeted therapy. These soluble factors can be detected in different bodily fluids, such as serum, plasma, and urine as a non-invasive method. There are lots of studies that have tried to show the importance of receptors and ligands in disorders; while a few studies tried to indicate the importance of soluble forms of receptors/ligands and their clinical aspects as a systemic compound and shedding of targets related to efferocytosis. Some of these soluble forms also can be as sensitive as specific biomarkers for certain diseases compared with routine biomarkers, such as soluble circulatory Lectin-like oxidized low-density lipoprotein receptor-1 vs. troponin T in the acute coronary syndrome. Thus, this review tried to gain more understanding about efferocytosis-related unwanted soluble receptors/ligands, their roles, the clinical significance, and potential for diagnosis, and prognosis related to different diseases.
... MVs/MPs have been also implicated in the pathogenesis of preeclampsia. Their plasma levels are higher, particularly in cases of early-onset preeclampsia.218,[223][224][225][226] While their cargo and mechanism of action have been less thoroughly investigated than those of sEVs, preeclampsia-related MVs/MPs contain more Flt-1 and activate endothelial cells and slow down their proliferation.101,218,226 ...
The mechanisms underlying maternal tolerance of the semi‐ or fully‐allogeneic fetus are intensely investigated. Across gestation, feto‐placental antigens interact with the maternal immune system locally within the trophoblast‐decidual interface and distantly through shed cells and soluble molecules that interact with maternal secondary lymphoid tissues. The discovery of extracellular vesicles (EVs) as local or systemic carriers of antigens and immune‐regulatory molecules has added a new dimension to our understanding of immune modulation prior to implantation, during trophoblast invasion, and throughout the course of pregnancy. New data on immune‐regulatory molecules, located on EVs or within their cargo, suggest a role for EVs in negotiating immune tolerance during gestation. Lessons from the field of transplant immunology also shed light on possible interactions between feto‐placentally derived EVs and maternal lymphoid tissues. These insights illuminate a potential role for EVs in major obstetrical disorders. This review provides updated information on intensely studied, pregnancy‐related EVs, their cargo molecules, and patterns of fetal‐placental‐maternal trafficking, highlighting potential immune pathways that might underlie immune suppression or activation in gestational health and disease. Our summary also underscores the likely need to broaden the definition of the maternal‐fetal interface to systemic maternal immune tissues that might interact with circulating EVs.
... Placental cells and tissues release exosomes, both in vitro and in vivo, and the abundance of placenta-derived exosomes in maternal blood seems to increase steadily during pregnancy, particularly during the first trimester [19]. Microparticle shedding from syncytiotrophoblasts has been described to be higher in pre-eclampsia than in normal pregnancy [20]. Exosomes have been investigated in many biology and disease models and are recognized to play critical roles in angiogenesis, immunomodulation, cell survival, cancer and inflammation; however, their importance in mediating embryo-maternal interactions, implantation, placental physiology and pregnancy has only recently been appreciated [21]. ...
Background
The high incidence of pre-eclampsia, which affects 2–7% of all pregnancies, remains a major health concern. Detection of pre-eclampsia before the appearance of clinical symptoms is essential to allow early intervention, and would benefit from identification of plasma/serum biomarkers to help guide diagnosis and treatment. Liquid biopsy has emerged as a promising source of protein biomarkers that circumvents some of the inherent challenges of proteome-wide analysis of plasma/serum. In this respect, purified exosomes have the added benefit of being carriers of intercellular communication both in physiological and pathological conditions.
Methods
We compared the protein complement of purified exosomes from three different collections of control and pre-eclamptic serum samples, obtained at the end of the second trimester of pregnancy and at delivery. We employed shotgun label-free proteomics to investigate differential protein expression, which was then validated by targeted proteomics.
Results
We developed a purification method that yielded highly enriched exosome preparations. The presence of specific pregnancy protein markers suggested that a significant proportion of purified exosomes derived from tissues related to pregnancy. Quantitative proteomic analyses allowed us to identify 10, 114 and 98 differentially-regulated proteins in the three sample collections, with a high degree of concordance. Functional analysis suggested that these proteins participate in biological processes related to pre-eclampsia, including angiogenesis, inflammation and cell migration. The differential abundance of 66 proteins was validated by targeted proteomics. Finally, we studied the impact of the pre-eclampsia-associated exosomes in the proteome using an in vitro cellular model.
Conclusions
We have identified and validated differential exosomal proteins in liquid biopsy of pregnant women that open new possibilities for early detection of pre-eclampsia. Additionally, the functional impact of the proteome composition of purified pre-eclamptic exosomes in target cells provides new information to better understand changes in embryo-maternal interactions and, consequently, the pathogenesis of this disease.
... Whereas in physiological pregnancies, the apoptosis process is exclusively regulated by the immune system through the extrinsic pathway in an FAS ligand (FASL) manner, the pathologic environment in PE leads to the activation of the intrinsic route and a decrease in anti-apoptotic proteins. This concludes with enhanced apoptosis of EVTs and STBs, with increased syncytial knots, a marker of accelerated aging in the placental tissue and in EO-PE [166,167]. The premature aging of placental tissue is also supported by the dysregulation of several hallmarks of aging, including telomere shortening, cell senescence, loss of proteostasis, epigenetic variations, and mitochondrial dysfunction, among others [168][169][170][171]. ...
The placenta is a central structure in pregnancy and has pleiotropic functions. This organ grows incredibly rapidly during this period, acting as a mastermind behind different fetal and maternal processes. The relevance of the placenta extends far beyond the pregnancy, being crucial for fetal programming before birth. Having integrative knowledge of this maternofetal structure helps significantly in understanding the development of pregnancy either in a proper or pathophysiological context. Thus, the aim of this review is to summarize the main features of the placenta, with a special focus on its early development, cytoarchitecture, immunology, and functions in non-pathological conditions. In contraposition, the role of the placenta is examined in preeclampsia, a worrisome hypertensive disorder of pregnancy, in order to describe the pathophysiological implications of the placenta in this disease. Likewise, dysfunction of the placenta in fetal growth restriction, a major consequence of preeclampsia, is also discussed, emphasizing the potential clinical strategies derived. Finally, the emerging role of the placenta in maternal chronic venous disease either as a causative agent or as a consequence of the disease is equally treated.
... Similarly, compared to normal pregnancies, increased total circulating exosomes were found in patients with early-and late-onset PE, but the significantly reduced PLAP + : total circulating exosome ratio suggests a potential role in these patients [112]. Further, enhanced STBM levels, as measured by ELISA, appear to occur during early-onset (< 34 weeks' gestation), but not late-onset, PE [113,114]. Although not well studied, elevated endothelial-derived microparticles were also reported in eclamptic patients [115]. ...
Extracellular vesicles are small membrane-enclosed particles released during cell activation or injury. They have been investigated for several decades and found to be secreted in various diseases. Their pathogenic role is further supported by the presence of several important molecules among their cargo, including proteins, lipids, and nucleic acids. Many studies have reported enhanced and targeted extracellular vesicle biogenesis in diseases that involve chronic or transient elevation of arterial pressure resulting in endothelial dysfunction, within either the general circulatory system or specific local vascular beds. In addition, several associated pathologic processes have been studied and reported. However, the role of elevated pressure as a common pathogenic trigger across vascular domains and disease chronicity has not been previously described. This review will therefore summarize our current knowledge of the differential and targeted biogenesis of extracellular vesicles in major diseases that are characterized by elevated arterial pressure leading to endothelial dysfunction and propose a unified theory of pressure-induced extracellular vesicle-mediated pathogenesis.
... In the placenta, PEBP1 has been suggested to regulate trophoblast migration and is expressed in villous cytotrophoblasts while its expression is translocated to the syncytium in PE placentas [70]. Due to syncytiotrophoblast stress in PE, there is an increased production and shedding of vesicles compared to normal pregnancies [71]. A key depolymerizer of actin filaments also found in a hypomethylated region in PE is MICAL1, which regulates actin cytoskeleton dynamics in a variety of processes from cytokinesis [72] to invasion and mobility in cancer [73]. ...
Exposure to ambient air pollution during pregnancy has been associated with an increased risk of preeclampsia (PE). Some suggested mechanisms behind this association are changes in placental DNA methylation and gene expression. The objective of this study was to identify how early pregnancy exposure to ambient nitrogen oxides (NOx) among PE cases and normotensive controls influence DNA methylation (EPIC array) and gene expression (RNA-seq). The study included placentas from 111 women (29 PE cases/82 controls) in Scania, Sweden. First-trimester NOx exposure was assessed at the participants’ residence using a dispersion model and categorized via median split into high or low NOx. Placental gestational epigenetic age was derived from the DNA methylation data. We identified six differentially methylated positions (DMPs, q < 0.05) comparing controls with low NOx vs. cases with high NOx and 14 DMPs comparing cases and controls with high NOx. Placentas with female fetuses showed more DMPs (N = 309) than male-derived placentas (N = 1). Placentas from PE cases with high NOx demonstrated gestational age deceleration compared to controls with low NOx (p = 0.034). No differentially expressed genes (DEGs, q < 0.05) were found. In conclusion, early pregnancy exposure to NOx affected placental DNA methylation in PE, resulting in placental immaturity and showing sexual dimorphism.
... Trophoblasts release a diverse spectrum of hormones, growth factors and extracellular vesicles (EV) from the first trimester onwards [89,90]. The amount of released EVs increases with ongoing gestation, and pathological pregnancies show a further significant increase [91,92]. EVs are shed from the SCT into the IVS and, therefore, directly into the maternal blood circulation. ...
Upon activation, maternal platelets provide a source of proinflammatory mediators in the intervillous space of the placenta. Therefore, platelet-derived factors may interfere with different trophoblast subtypes of the developing human placenta and might cause altered hormone secretion and placental dysfunction later on in pregnancy. Increased platelet activation, and the subsequent occurrence of placental fibrinoid deposition, are linked to placenta pathologies such as preeclampsia. The composition and release of platelet-derived factors change over gestation and provide a potential source of predicting biomarkers for the developing fetus and the mother. This review indicates possible mechanisms of platelet-trophoblast interactions and discusses the effect of increased platelet activation on placenta development.
... 21 These endothelial changes can also be due to oxidative stress. 8 The gut microbiota plays an important role in lowering blood pressure, 22 reducing inflammation, 23 hemostasis, glucose metabolism, 24 and body mass index. 25 These supplements play a positive role in reducing oxidative stress and systemic inflammation. ...
Introduction: Antioxidants and anti-inflammatory drugs have been suggested to treat preeclampsia. This systematic review and meta-analysis was conducted to investigate the efficacy of probiotic or synbiotic supplementation on hypertensive disorders in women with gestational diabetes mellitus (GDM)
. Methods: The databases including Cochrane, Embase, Ovid, ProQuest, Scopus, Web of Science, and PubMed were systematically searched for collecting the randomized controlled trials (RCTs) investigating the efficacy of probiotic or synbiotic supplementation versus placebo on hypertensive disorders and pregnancy outcomes in GDM until July 2020.
Results: Five RCTs with a total sample size of 402 women were included in the meta-analysis. There was no significant decline in systolic blood pressure (standardized mean difference [SMD]=-3.41, 95% confidence interval [CI]=-8.32 to 1.50, P=0.17), diastolic blood pressure (SMD=-5.11, 95% CI=-14.20 to -3.98, P=0.27), preeclampsia (odds ratio [OR]=1.56, 95% CI=0.61 to 3.98, P=0.35), cesarean section (OR=0.52, 95% CI=0.18 to 1.50, P=0.23), and macrosomia (OR=0.81, 95% CI=0.41 to 1.57, P=0.53). No significant increase was observed in terms of 5-minute Apgar (SMD=0.16, 95% CI=-0.06 to 0.39, P=0.15, I²=0%), birth weight (SMD=-0.18, 95% CI=-0.43 to 0.06, P=0.13, I²=0%), and gestational age (SMD=0.13, 95% CI=-0.11 to 0.37, P=0.28, I²=0%).
Conclusion: Probiotic or synbiotic supplements are not associated with significant effects on pregnancy outcomes in GDM. However, due to the limited number of studies in this regard and heterogeneity between studies, future high-quality RCTs are recommended.
... В то же время группа исследователей из Китая (2018 г.) не обнаружила изменений общего уровня EVs материнского происхождения при развитии преэклампсии, при этом указав на увеличение концентрации эндотелиальных EVs и снижение тромбоцитарных EVs в общей структуре [16]. Интересно отметить, что повышение общего уровня EVs материнского происхождения характерно для ранней (плацентарной) преэклампсии [17] и неспецифично для поздней (материнской) преэклампсии [18]. Разнонаправленное изменение уровня различных EVs материнского происхождения при развитие тяжелой преэклампсии представлено в табл. 1. ...
Pre-eclampsia is a clinically unfavorable pregnancy outcome that determines the main indicators of maternal and/or perinatal morbidity and mortality. According to modern concepts, the placenta plays a central role in the development of PE, while intercellular and intervesicular communications involving extracellular vesicles (EVs, extracellular vesicles) initiate a cascade of various biological effects, determining the mechanisms of ontogenesis of the gestational process in normal and pathological conditions. Achievements in studies of extracellular vesicles (EVs, extracellular vesicles) are of particular interest both to clinicians and to researchers studying the pathophysiology of gestational complications. Extracellular vesicles (EVs) in preeclampsia are produced both by scintiotrophoblast and the maternal body - blood cells (platelets, red blood cells, white blood cells) and the cardiovascular (vascular endothelium, smooth muscle) system. Changes in the concentration of these EVs can contribute to the implementation of preeclampsia, enhancing the pro-inflammatory and procoagulant states inherent in the gestation process. This review focuses on freely available information on the possible interactions between placental and maternal EVs. Understanding the contribution of EVs to the development of preeclampsia can help to deepen knowledge about the pathogenesis of this pathology and determine the diagnostic and prognostic significance of extracellular vesicles as biomarkers.
The endoplasmic reticulum (ER) is a complex and dynamic organelle that initiates unfolded protein response (UPR) and endoplasmic reticulum stress (ER Stress) in response to the accumulation of unfolded or misfolded proteins within its lumen. Autophagy is a paramount intracellular degradation system that facilitates the transportation of proteins, cytoplasmic components, and organelles to lysosomes for degradation and recycling. Preeclampsia (PE) and intrauterine growth retardation (IUGR) are two common complications of pregnancy associated with abnormal trophoblast differentiation and placental dysfunctions and have a major impact on fetal development and maternal health. The intricate interplay between ER Stress, and autophagy and their impact on pregnancy outcomes, through mediating trophoblast differentiation and placental development, has been highlighted in various reports. Autophagy controls trophoblast regulation through a variety of gene expressions and signalling pathways while excessive ER Stress triggers downstream apoptotic signalling, culminating in trophoblast apoptosis. This comprehensive review delves into the intricacies of placental development and explores the underlying mechanisms of PE and IUGR. In addition, this review will elucidate the molecular mechanisms of ER Stress and autophagy, both individually and in their interplay, in mediating placental development and trophoblast differentiation, particularly highlighting their roles in PE and IUGR development. This research seeks to the interplay between ER Stress and impaired autophagy in the placental trophoderm, offering novel insights into their contribution to pregnancy complications.
Dysferlinopathies refer to a spectrum of muscular dystrophies that cause progressive muscle weakness and degeneration. They are caused by mutations in the DYSF gene, which encodes the dysferlin protein that is crucial for repairing muscle membranes. This review delves into the clinical spectra of dysferlinopathies, their molecular mechanisms, and the spectrum of emerging therapeutic strategies. We examine the phenotypic heterogeneity of dysferlinopathies, highlighting the incomplete understanding of genotype-phenotype correlations and discussing the implications of various DYSF mutations. In addition, we explore the potential of symptomatic, pharmacological, molecular, and genetic therapies in mitigating the disease’s progression. We also consider the roles of diet and metabolism in managing dysferlinopathies, as well as the impact of clinical trials on treatment paradigms. Furthermore, we examine the utility of animal models in elucidating disease mechanisms. By culminating the complexities inherent in dysferlinopathies, this write up emphasizes the need for multidisciplinary approaches, precision medicine, and extensive collaboration in research and clinical trial design to advance our understanding and treatment of these challenging disorders.
The "exposome" covers all disease determinants across a lifetime. Many exposome factors could induce epigenetic changes, especially in DNA methylation. Yet, the role of these modifications in disease development remains partly understood.
Although the possible relationship among the exposome factors, epigenetic modifications, and health/disease has been investigated extensively, all previous studies start from the assumption that epigenetic changes are always detrimental to (or represent an adverse effect on) the health of the affected individual. We hereby propose a new approach to investigate these modifications, and their possible relation with human health, in the context of the exposome.
Our hypothesis is based on the possibility that some environmentally-induced changes are plastic entities, responding physiologically to the environment to allow individual adaptation. Briefly, after evaluating the association between environmental exposure and the variation of a given biological parameter through regression models, we use the estimated regression function to predict values for each study subject. We then calculated the relative percent difference (PD) between the measured (i.e., observed) biological parameter and the predicted (i.e., expected) from the model. Notably, we have tested our hypothesis using two distinct models, specifically focusing on LINE-1 methylation and extracellular vesicles (EVs). We hypothesize that the greater the difference between the observed and the expected, the greater the inability of the subject to adapt to external stimuli.
Extracellular vesicles (EVs) play a crucial role in pregnancy, revealed by the presence of placental‐derived EVs in maternal blood, their in vitro functionality, and their altered cargo in pregnancy pathologies. These EVs are thought to be involved in the development of pregnancy pathologies, such as pre‐eclampsia, pre‐term birth, and fetal growth restriction, and have been suggested as a source of biomarkers for gestational diseases. However, to accurately interpret their function and biomarker potential, it is necessary to critically evaluate the EV isolation and characterization methodologies used in pregnant cohorts. In this systematic scoping review, we collated the results from 152 studies that have investigated EVs in the blood of pregnant women, and provide a detailed analysis of the EV isolation and characterization methodologies used. Our findings indicate an overall increase in EV concentrations in pregnant compared to non‐pregnant individuals, an increased EV count as gestation progresses, and an increased EV count in some pregnancy pathologies. We highlight the need for improved standardization of methodology, greater focus on gestational changes in EV concentrations, and further investigations into the functionality of EVs. Our review suggests that EVs hold great promise as diagnostic and translational tools for gestational diseases. However, to fully realize their potential, it is crucial to improve the standardization and reliability of EV isolation and characterization methodologies, and to gain a better understanding of their functional roles in pregnancy pathologies.
ABSTRACT
Aims: We aimed to investigate the level and predictive value of soluble nectin-4 in early onset preeclampsia (EOPE).
Methods: Forty-three patients with EOPE and 41 healthy normotensive pregnant women participated in this prospective
case-control study. The groups were matched for gestational age and gravidity. Serum nectin-4 levels were compared between
groups. The ROC curve was drawn to show the predictive value of nectin-4 for EOPE. Patients were followed up until the end
of labor, and perinatal outcomes were recorded.
Results: The demographic characteristics of the two groups were similar. Serum nectin-4 level was significantly increased in
EOPE cases compared to controls (226.46±119.6 ng/ml vs. 156.54±44.8 ng/ml, p=0.001). The ROC showed that at > 160.938,
the sensitivity and specificity were 67.44% and 82.93%, respectively [AUC:0.822, (CI:0.724 - 0.897), and (p< 0.001)]. Significant
inverse correlations were found between nectin-4 levels and poor obstetric outcomes.
Conclusion: Maternal serum nectin-4 levels were significantly higher in patients with EOPE compared with controls. Increased
nectin-4 levels may contribute to the development of EOPE through possible oxidative, immunological, and inflammatory
mechanisms adversely affecting trophoblastic cells.
Keywords: Early preeclampsia, nectin-4, preeclampsia, pregnancy
Problem
Considerable evidence suggests that placental extracellular vesicles (EVs) interact with most types of leukocytes in vitro but in vivo biodistribution studies question whether these interactions are reflective of the situation in vivo.
Method of Study
CellTracker Red CMTPX stained human placental micro‐EVs were isolated from first trimester placental explant cultures. Equivalent amounts of micro‐EVs were cultured with murine leukocytes in vitro or injected into pregnant or non‐pregnant mice. After intravenous injection, on day 12.5 of gestation, major organs and blood samples were harvested 30 min or 24 h post injection.
Results
We screened cryosections of the organs and confirmed that human placental EVs were specifically localised to the spleen, liver and the lungs 30 min or 24 h after injection. Immunohistochemistry showed that most of the EVs interacted with macrophages in those three organs and some of them also associated with T and B lymphocytes in the spleen or endothelial cells in the lungs and liver. Flow cytometry demonstrated that there was very little interaction between circulating leukocytes and EVs in vivo. While minimal, significantly more EVs interacted with leukocytes in pregnant than nonpregnant mice.
Conclusion
The major interaction between human placental micro‐EVs and maternal leukocytes appear to be with macrophages predominantly in the splenic marginal zone, liver and lungs with little interaction between EVs and circulating leukocytes. Since marginal zone macrophages induce tolerance after phagocytosing apoptotic bodies it is likely that phagocytosis of placental EVs by marginal zone macrophages may also contribute to maternal immune tolerance.
The Siglecs family is a group of type I sialic acid-binding immunoglobulin-like receptors that regulate cellular signaling by recognizing sialic acid epitopes. Siglecs are predominantly expressed on the surface of leukocytes, where they play a crucial role in regulating immune activity. Pathogens can exploit inhibitory Siglecs by utilizing their sialic acid components to promote invasion or suppress immune functions, facilitating immune evasion. The establishing of an immune-balanced maternal-fetal interface microenvironment is essential for a successful pregnancy. Dysfunctional immune cells may lead to adverse pregnancy outcomes. Siglecs are important for inducing a phenotypic switch in leukocytes at the maternal-fetal interface toward a less toxic and more tolerant phenotype. Recent discoveries regarding Siglecs in the reproductive system have drawn further attention to their potential roles in reproduction. In this review, we primarily discuss the latest advances in understanding the impact of Siglecs as immune regulators on infections and pregnancy.
Background:
Preeclampsia is a major cause of maternal and perinatal morbidity and mortality worldwide. Identifying women with high risk of developing preeclampsia in early pregnancy remains challenging. Extracellular vesicles released from the placenta offer an attractive biomarker but have been elusive to quantify.
Methods:
Here, we tested ExoCounter, a novel device that immunophenotypes size-selected small extracellular vesicles <160 nm, for its ability to perform qualitative and quantitative placental small extracellular vesicles (psEV) analysis. To investigate disease-specific and gestational age-specific changes, we analyzed psEV counts in maternal plasma samples taken at each of the 3 trimesters from women who had (1) normal pregnancy (n=3); (2) women who developed early-onset preeclampsia ([EOPE], n=3); and (3) women who developed late-onset preeclampsia (n=4) using 3 antibody pairs, CD10-placental alkaline phosphatase (PLAP), CD10-CD63, and CD63-PLAP. We further validated the findings in first-trimester serum samples among normal pregnancy (n=9), women who developed EOPE (n=7), and women who developed late-onset preeclampsia (n=8).
Results:
We confirmed that CD63 was the major tetraspanin molecule coexpressed with PLAP-a known placental extracellular vesicles marker on psEV. Higher psEV counts for all 3 antibody pairs were detected in the plasma of women who developed EOPE than the other 2 groups in the first trimester, which persisted through the second and third trimesters. Significantly higher CD10-PLAP (P<0.01) and CD63-PLAP (P<0.01) psEV counts were validated in the serum of the first trimester of women who developed EOPE compared with normal pregnancy.
Conclusions:
Application of the ExoCounter assay developed here could identify patients at risk of developing EOPE in the first trimester, thereby providing a window of opportunity for early intervention.
Problem:
Immunomodulation profoundly affects the process of human implantation. Trophoblast cell-derived microparticles (Tr-MPs) may activate specific T cells to attack trophoblast cells, thus potentially acting as an immunocontraceptive vaccine. The safety and persistence of Tr-MP vaccine are needed to address.
Method of study:
Flow cytometry and confocal fluorescent microscopy were conducted to detect cellular absorptivity and localization of Tr-MPs in bone marrow-derived dendritic cells (BMDCs). The phenotype and cytokine secretion of BMDC and T cells were performed by flow cytometry and enzyme-linked immuno sorbent assay (ELISA). The constructed vaccine female moused model were used to observe the infertile effect and safety of Tr-MPs.
Results:
As compared with non-irradiation exposure groups, the number of MPs released by trophoblast cells in ultraviolet immunized groups significantly increased. The phagocytosis of Tr-MPs led to the maturation of dendritic cells (DCs), which, in turn, activate T cells. Then cytotoxic T cells attacking trophoblast cells. In mouse model, female mice were infertile after receiving Tr-MPs, and the effect of contraception is transient and safety.
Conclusion:
Using Tr-MPs to initiate an adaptive immune response against alloantigens in trophoblast cells. Tr-MPs may be a new candidate for the development of contraceptive vaccines due to its effectiveness, safety, and reversibility.
Preeclampsia is a pregnancy-related multisystem disorder characterized by altered trophoblast invasion, oxidative stress, exacerbation of systemic inflammatory response, and endothelial damage. The pathogenesis includes hypertension and mild-to-severe microangiopathy in the kidney, liver, placenta, and brain. The main mechanisms involved in its pathogenesis have been proposed to limit trophoblast invasion and increase the release of extracellular vesicles from the syncytiotrophoblast into the maternal circulation, exacerbating the systemic inflammatory response. The placenta expresses glycans as part of its development and maternal immune tolerance during gestation. The expression profile of glycans at the maternal–fetal interface may play a fundamental role in physiological pregnancy changes and disorders such as preeclampsia. It is unclear whether glycans and their lectin-like receptors are involved in the mechanisms of maternal–fetal recognition by immune cells during pregnancy homeostasis. The expression profile of glycans appears to be altered in hypertensive disorders of pregnancy, which could lead to alterations in the placental microenvironment and vascular endothelium in pregnancy conditions such as preeclampsia. Glycans with immunomodulatory properties at the maternal–fetal interface are altered in early-onset severe preeclampsia, implying that innate immune system components, such as NK cells, exacerbate the systemic inflammatory response observed in preeclampsia. In this article, we discuss the evidence for the role of glycans in gestational physiology and the perspective of glycobiology on the pathophysiology of hypertensive disorders in gestation.
In this chapter, two important placenta-associated pregnancy syndromes are described: preeclampsia and fetal growth restriction/intra-uterine growth restriction (FGR/IUGR). For both disorders, the sequences of development are still largely unclear. Therefore, the first section attempts to summarize the current hypotheses on the development of both syndromes and to contrast them with the old hypotheses. The decisive role of the interplay between mother and placenta becomes apparent. The second section covers the diagnosis and management of fetal growth restriction and what major studies are currently underway to determine the best care for the child. The final section covers the diagnosis and management of preeclampsia. This also includes information on predictive biomarkers, risk assessment in the first trimester, and long-term illnesses due to preeclampsia.
Preeclampsia (PE) is a pregnancy syndrome characterized by new-onset hypertension and end-organ dysfunction. The pathophysiology of PE remains undetermined, but it is thought that maternal vascular dysfunction plays a central role, potentially due, in part, to the release of syncytiotrophoblast-derived extracellular vesicles (STBEVs) into the maternal circulation by a dysfunctional placenta. STBEVs from normal pregnancies (NP) impair vascular function, but the effect of PE STBEVs (known to differ in composition with elevated circulating levels) on vascular function are not known. We hypothesized that PE STBEVs have more detrimental effects on vascular function compared to NP STBEVs. STBEVs were collected by perfusion of placentas from women with NP or PE. Mesenteric arteries from pregnant rats were incubated overnight with NP or PE STBEVs, and vascular function was assessed by wire myography. NP and PE STBEVs impaired endothelial function, partially by reducing nitric oxide (NO) bioavailability. Incubation of human umbilical vein endothelial cells with NP and PE STBEVs increased NF-κB activation, reactive oxygen species, nitrotyrosine levels, and reduced NO levels. However, PE STBEVs increased NF-κB activation and nitrotyrosine levels to a lesser extent than NP STBEVs. Taken together, no greater impact of PE STBEVs compared to NP STBEVs on endothelial function was found. However, the impaired vascular function by PE STBEVs and increased levels of STBEVs in PE suggest PE STBEVs may contribute to maternal vascular dysfunction in PE. Our study further expands on the potential mechanisms that lead to adverse outcomes in PE and provides potential targets for future interventions.
Preeclampsia (PE), defined as new-onset hypertension and multi-organ systemic complication during pregnancy, is the leading cause of maternal and neonatal mortality and morbidity. With extracellular vesicles research progresses, current data refers to the possibility that ferroptosis may play a role in exosomal effects. Evidence has suggested that ferroptosis may contribute to the pathogenesis of preeclampsia by bioinformatics analyses. The purpose of the current study is to identify the potential ferroptosis-related genes in syncytiotrophoblast-derived extracellular vesicles (STB-EVs) of preeclampsia using bioinformatics analyses. Clinical characteristics and gene expression data of all samples were obtained from the NCBI GEO database. The differentially expressed mRNAs (DE-mRNAs) in STB-EVs of preeclampsia were screened and then were intersected with ferroptosis genes. Functional and pathway enrichment analyses of ferroptosis-related DE-mRNAs in STB-EVs were performed. Ferroptosis-related hub genes in STB-EVs were identified by Cytoscape plugin CytoHubba with a Degree algorithm using a protein-protein interaction network built constructed from the STRING database. The predictive performance of ferroptosis-related hub genes was determined by a univariate analysis of receiver operating characteristic (ROC). The miRNA-hub gene regulatory network was constructed using the miRwalk database. A total of 1976 DE-mRNAs in STB-EVs were identified and the most enriched item identified by gene set enrichment analysis was signaling by G Protein-Coupled Receptors (normalized enrichment score = 1.238). These DE-mRNAs obtained 26 ferroptosis-related DE-mRNAs. Ferroptosis-related DE-mRNAs of gene ontology terms and Encyclopedia of Genes and Genomes pathway enrichment analysis were enriched significantly in response to oxidative stress and ferroptosis. Five hub genes (ALB, NOX4, CDKN2A, TXNRD1, and CAV1) were found in the constructed protein-protein interaction network with ferroptosis-related DE-mRNAs and the areas under the ROC curves for ALB, NOX4, CDKN2A, TXNRD1, and CAV1 were 0.938 (CI: 0.815-1.000), 0.833 (CI: 0.612-1.000), 0.875 (CI: 0.704-1.000), 0.958 (CI: 0.862-1.000), and 0.854 (CI: 0.652-1.000) in univariate analysis of ROC. We constructed a regulatory network of miRNA-hub gene and the findings demonstrate that hsa-miR-26b-5p, hsa-miR-192-5p, hsa-miR-124-3p, hsa-miR-492, hsa-miR-34a-5p and hsa-miR-155-5p could regulate most hub genes. In this study, we identified several central genes closely related to ferroptosis in STB-EVs (ALB, NOX4, CDKN2A, TXNRD1, and CAV1) that are potential biomarkers related to ferroptosis in preeclampsia. Our findings will provide evidence for the involvement of ferroptosis in preeclampsia and improve the understanding of ferroptosis-related molecular pathways in the pathogenesis of preeclampsia.
The impact of exposure to respirable particulate matter (PM) during pregnancy is a growing concern, as several studies have associated increased risks of adverse pregnancy and birth outcomes, and impaired intrauterine growth with air pollution. The molecular mechanisms responsible for such effects are still under debate. Extracellular vesicles (EVs), which travel in body fluids and transfer microRNAs (miRNAs) between tissues (e.g., pulmonary environment and placenta), might play an important role in PM-induced risk. We sought to determine whether the levels of PM with aerodynamic diameters of ≤10 µm (PM10) and ≤2.5 µm (PM2.5) are associated with changes in plasmatic EV release and EV-miRNA content by investigating 518 women enrolled in the INSIDE study during the first trimester of pregnancy. In all models, we included both the 90-day averages of PM (long-term effects) and the differences between the daily estimate of PM and the 90-day average (short-term effects). Short-term PM10 and PM2.5 were associated with increased concentrations of all seven EV types that we assayed (positive for human antigen leukocyte G (HLA-G), Syncytin-1 (Sync-1), CD14, CD105, CD62e, CD61, or CD25 determinants), while long-term PM10 showed a trend towards decreased EV concentrations. Increased Sync-1 + EV levels were associated with the plasmatic decrease of sVCAM-1, but not of sICAM-1, which are circulating biomarkers of endothelial dysfunction. Thirteen EV-miRNAs were downregulated in response to long-term PM10 and PM2.5 variations, while seven were upregulated (p-value
S100 proteins bind Ca²⁺ and regulate various signaling pathways inside and outside the cell. They are expressed in vertebrates and exhibit tissue and cell specific distribution. Of note, increased level of S100 proteins is observed in different pathologies such as cancers, nervous system diseases/neurodegeneration, inflammation or cardiovascular diseases. Certain S100 proteins can be found in serum and/or other body fluids, at an especially high level in pathological states. Thus, S100 proteins might serve as diagnostic markers in the clinic. Interestingly, expression of many S100 proteins is found to be associated with pregnancy, which suggests that alterations in their expression during pregnancy may regulate processes involved in embryo/fetus formation. In this review we summarize available literature data concerning the expression and possible function of S100 proteins in a disease of pregnant women known as preeclampsia or EPH-gestosis.
In this chapter we have turned to the outstanding expertise of Graham Burton and his colleagues at the Physiological Laboratory at Cambridge. Here the reader will find a detailed description of the microanatomical development of the fetal–maternal interface, particularly as it relates to the biomechanics of the growing placental vasculature. Clinical correlations with high-resolution radiological imaging findings are included. The critical roles of oxygen tension, cell stress, and senescence also are highlighted. Drawing from these experts in the field, students of preeclampsia will be able to appreciate the integrated roles of form and function in the placenta’s normal physiology and under disease states.
In the early 1980s, physicians and scientists began to gain an appreciation of the physiological importance of the endothelium, the simple unicellular layer lining the luminal surface of blood vessels. Indeed, in Chesley's first, single-authored edition of this text, the reference to this term was confined to the “endotheliosis” lesion of the renal glomerulus. We now recognize that endothelial cells are critical sensors of the milieu interieur and potent regulators of vascular tone, organ perfusion, and ischemia. The “endothelial hypothesis” of preeclampsia etiology provides for a convergence of several factors thought to play fundamental roles in its pathogenesis: leukocytes, platelets, cytokines, fatty acids, oxygen free radicals, placental microvesicles, cell-free DNA fragments, “antiangiogenic” factors, and autoantibodies are all considered.
The syncytiotrophoblast (STB), a fused single-cell layer of the placenta is the interface between mother and fetus. The STB constitutively releases extracellular vesicles (STBEV) directly into the maternal circulation. STBEV contain a variety of proteins and RNA which target specific cells. In preeclampsia, asymptomatic placental oxidative stress is a precursor to later multi-organ dysfunction in the mother. Increased STBEV release in preeclampsia is considered to be a consequence of syncytiotrophoblast stress. These STBEV may play a key role in signaling between fetus and mother. STBEV release in preeclampsia changes, both in terms of volume and content. In this chapter, we summarise studies to date demonstrating STBEV actions on target cells. We consider how STBEV fit into the pathophysiology of the heterogeneous syndrome of preeclampsia. We propose that STBEV are the key stress signal in preeclampsia and can explain a large part of the heterogeneity of the disease. We believe that further investigation of STBEV release, content, and actions may offer valuable insights into preeclampsia pathophysiology and potential new clinical diagnostics and therapeutic targets.
Background:
Preeclampsia (PE) manifesting as hypertension and organ injury is mediated by vascular dysfunction. In biological fluids, extracellular vesicles (EVs) containing microRNA (miRNA), protein, and other cargo released from the placenta may serve as carriers to propagate injury, altering the functional phenotype of endothelial cells. PE has been consistently correlated with increased levels of placenta-derived EVs (pEVs) in maternal circulation. However, whether pEVs impaired endothelial cell function remains to be determined. In this study, we hypothesize that pEVs from pregnant women with severe PE (sPE) impair endothelial function through altered cell signaling.
Methods:
We obtained plasma samples from women with sPE (n = 14) and normotensive pregnant women (n = 15) for the isolation of EVs. The total number of EV and pEV contribution was determined by quantifying immunoreactive EV-cluster of designation 63 (CD63) and placental alkaline phosphatase (PLAP) as placenta-specific markers, respectively. Vascular endothelial functional assays were determined by cell migration, electric cell-substrate impedance sensing in human aortic endothelial cells (HAECs), and wire myography in isolated blood vessels, preincubated with EVs from normotensive and sPE women.
Results:
Plasma EV and pEV levels were increased in sPE when compared to normotensive without a significant size distribution difference in sPE (108.8 ± 30.2 nm) and normotensive-EVs (101.3 ± 20.3 nm). Impaired endothelial repair and proliferation, reduced endothelial barrier function, reduced endothelial-dependent vasorelaxation, and decreased nitrite level indicate that sPE-EVs induced vascular endothelial dysfunction. Moreover, sPE-EVs significantly downregulated endothelial nitric oxide synthase (eNOS and p-eNOS) when compared to normotensive-EV.
Conclusions:
EVs from sPE women impair endothelial-dependent vascular functions in vitro.
An examination of the maternal vascular response to placentation shows that physiological changes in the placental bed normally extend from the decidua into the inner myometrium. In pre-eclampsia and in a proportion of pregnancies with small-for-gestational age infants (SGA) the physiological changes are restricted to the decidual segments alone. In addition, complete absence of physiological changes throughout the entire length of some spiral arteries is seen in pre-eclampsia and SGA. This new observation is confirmed in a study of basal plates of placentas from abnormal pregnancies. Intraluminal endovascular trophoblast may be seen in the placental bed spiral arteries in the third trimester in pre-eclampsia and SGA, a feature not seen beyond the second trimester in normal pregnancy. These findings point to a defect in the normal interaction between migratory trophoblast and maternal uterine tissues in pre-eclampsia and in SGA.
Objective The origins of pre-eclampsia/eclampsia lie in a mismatch between feto-placental demands and utero-placental supply, a situation that also arises in normotensive intrauterine growth restriction (IUGR). Could reactivated chronic infection be both a trigger for these differential maternal responses to the same underlying pathology and a link between pre-eclampsia and its attendant lifelong risks of atherosclerosis? Design Nested case-control study. Setting Tertiary obstetric centre. Population Cases of pre-eclampsia, normotensive lUGR and controls. Methods A nested case-control study of serum from a population-based bank was performed. Seroprevalence and levels of anti-cytomegalovirus (CMV) and Chlamydophila pneumoniae immunoglobulin G (IgG) were compared (non-parametrically) between women with early onset pre-eclampsia (<34 weeks of gestation, n = 9), late onset pre-eclampsia (&GE;34 + 0 weeks of gestation, n = 29), normotensive IUGR (birthweight less than third centile, n = 33) and matched normal pregnancy (n = 113, up to 2 per case). Results There was a significant difference in both anti-CMV and Chl. pneumoniae antibodies between groups (Kruskal-Wallis test, P < 0.05). Women with early onset pre-eclampsia had higher anti-CMV levels (median: 79, 95% confidence interval [95% Cl] = 47, 164) than women with late onset pre-eclampsia (26 [95% Cl = 22, 82], P < 0.05), normotensive lUGR (40 [95% Cl = 31, 72], P < 0.05) and normal pregnancy (49 [95% Cl = 45, 70], P < 0.05). Women with normotensive lUGR had significantly lower anti-Chl. pneumoniae antibodies (0.10 [95% Cl = 0.08, 0.38]) than did normal pregnancy controls (0.21 [95% Cl + 0.20, 0.28], P < 0.05). Conclusions The anti-CMV and anti-Chl. pneumoniae antibodies were higher in early onset pre-eclampsia than in late onset pre-eclampsia, normotensive lUGR and normal pregnancy. This may provide a pathophysiological link between pre-eclampsia and the known increased risk for subsequent atherosclerosis.
Within the human placenta the villous trophoblast represents the epithelial covering of the chorionic villi. This layer of trophoblast actively participates in transport processes between mother and fetus and is the surface of the barrier separating maternal and fetal blood. It represents the main site of metabolic and endocrine activities of the placenta. It is comprised of an outer continuous layer without cell borders, the syncytiotrophoblast, beneath which resides a population of proliferating cytotrophoblast cells. Daughter cytotrophoblast cells fuse into the syncytium, while aged nuclei inside syncytial fragments are shed into the maternal circulation (Figure 1). Any process disturbing the balance between proliferation, syncytial fusion or shedding will alter the integrity and function of the layer as a whole, which in turn may impair gas and/or nutrient transfer to the fetus as well as endocrine activities. Trophoblast turnover is thus tightly regulated to ensure normal fetal development.
Objective To investigate the hypothesis that, should there be an increase in deported syncytiotrophoblast microvillous membrane fragments in pre-eclampsia, it may cause maternal vascular endothelial dysfunction.
Design Syncytiotrophoblast microvillous membrane (STEM) vesicles, prepared from normal term placentae, were perfused through small subcutaneous arteries isolated from fat biopsies obtained at caesarean section. Endothelial function of these arteries was studied by determining acetylcholine-induced relaxation after preconstriction with noradrenaline. As controls, physiological buffer or red blood cell membranes in physiological buffer were used and endothelial function similarly estimated. Transmission electron microscopy was performed on arteries after perfusion.
Sample STBM vesicles, isolated from the placentae of three healthy women undergoing elective caesarean section for reasons unrelated to pre-eclampsia, were suspended in physiological buffer. Subcutaneous fat arteries were obtained from a separate group of 13 normotensive pregnant women, also undergoing elective caesarean section at term.
Results Perfusion with red blood cell membranes or physiological buffer had no significant effect on the concentration dependent relaxation in arteries preconstricted with noradrenaline. However, after 2 h perfusion with STBM vesicles, arteries showed a significant reduction in relaxation to acetylcholine, indicative of altered endothelial function. Transmission electron microscopy of arteries perfused with STBM vesicles confirmed endothelial disruption.
Conclusions STBM vesicle perfusion specifically altered the relaxation response of preconstricted maternal subcutaneous fat arteries to acetylcholine, suggesting an alteration in endothelial dependent relaxation. Deported microvilli may therefore be capable of producing endothelial cell damage and endothelial dysfunction observed in the maternal syndrome of pre-eclampsia.
Preeclampsia is a pregnancy-specific condition, and can be considered to have two component syndromes: maternal, characterized by hypertension and proteinuria, and fetal, manifested by intrauterine growth restriction (IUGR). Maternal deaths due to severe preeclampsia most commonly follow the onset of neutrophil-mediated complications, hepatocellular necrosis and the acute respiratory distress syndrome (ARDS). Hepatocellular necrosis and ARDS are both features of the systemic inflammatory response syndrome (SIRS). Preeclampsia may persist, often deteriorating transiently, following the delivery of the placenta, much as SIRS persists following the resolution of trauma, burns or sepsis. In both conditions there is a systemic response with inflammatory mediator release, endothelial cell dysfunction, a hyperdynamic state, end organ hypoperfusion, and neutrophil activation, resulting in the clinical syndromes. Both preeclampsia and SIRS result from differential responses to initiating factors. Preeclampsia results from incomplete placentation, which also underlies the development of intrauterine growth restriction in isolation (without preeclampsia). Similarly, sepsis, trauma and burns also occur in patients who have unremarkable recoveries rather than developing SIRS. Is preeclampsia a form of SIRS?
Despite intense study preeclampsia remains enigmatic and a major cause of maternal and fetal morbidity and mortality. Most investigative efforts have focused on the hypertensive component of this disorder with reduced attention given to other equally important characteristics. Increased sensitivity to pressor agents and activation of the coagulation cascade occur early in the course of preeclampsia, often antedating clinically recognizable disease. Inasmuch as endothelial cell injury reduces the synthesis of vasorelaxing agents, increases the production of vasoconstrictors, impairs synthesis of endogenous anticoagulants, and increases procoagulant production, these cells are likely to be implicated in the pathophysiology of preeclampsia. Indeed, evidence of endothelial cell injury is provided by the most characteristic morphologic lesion of preeclampsia, glomerular endotheliosis. Additional support for this hypothesis is derived from reports that indicate increased levels of circulating fibronectin (which can be released from injured endothelial cells) and increased factor VIII antigen present in the blood of preeclamptic women. More recently, direct evidence of activities that injure endothelial cells in vitro and increase the contractile sensitivity of isolated vessels has been presented. We propose that poorly perfused placental tissue releases a factor(s) into the systemic circulation that injuries endothelial cells. The changes initiated by endothelial cell injury set in motion a dysfunctional cascade of coagulation, vasoconstriction, and intravascular fluid redistribution that results in the clinical syndrome of preeclampsia.
Our purpose was to describe placental lesions associated with normal and abnormal fetal growth in infants delivered for obstetric indications at < 32 weeks' gestation.
Maternal and neonatal charts and placental tissues from 420 consecutive nonanomalous live-born singleton infants delivered at < 32 weeks' gestation with accurate gestational dates were retrospectively studied. Excluded were cases with maternal diabetes, chronic hypertension, hydrops fetalis, diagnosed congenital viral infection, and placenta previa, leaving four primary indications for delivery: preeclampsia, preterm labor, premature rupture of membranes, and nonhypertensive abruptio placentae. The presence and severity of placental lesions was scored by a pathologist blinded to clinical data. Birth weight and length percentiles were calculated from published nomograms. Asymmetric intrauterine growth retardation (n = 32) was defined as birth weight < 10th percentile with length > 10th percentile and symmetric intrauterine growth retardation (n = 48) as both weight and length < 10th percentile for gestational age. A "growth restriction index" was developed to express a continuum of growth in both length and weight. Contingency tables, analyses of variance, and multiple regression analysis defined significance as p < 0.05 (with corrections for multiple comparisons).
A greater proportion of cases with intrauterine growth retardation had lesions of uteroplacental insufficiency (p < 0.001) or chronic villitis (p < 0.02) than did appropriately grown preterm infants. Cases with asymmetric intrauterine growth retardation tended to have more lesions than did cases with appropriate-for-gestational-age infants. Four multiple regression analyses used the growth restriction index as outcome and the histologic lesion that had significant relationships to fetal growth as independent predictors in univariate analyses. Overall, uteroplacental fibrinoid necrosis, circulating nucleated erythrocytes, avascular terminal villi, and villous infarct were significant independent predictors of fetal growth (adjusted R2 = 0.312). With addition of preeclampsia as a variable, villous fibrosis, avascular villi, infarct, and preeclampsia were independent predictors of fetal growth (adjusted R2 = 0.341). In the 65 preeclampsia cases no histologic lesion was an independent predictor of fetal growth, whereas in the nonpreeclampsia cases, villous fibrosis and avascular villi were independent predictors of fetal growth (adjusted R2 = 0.075).
In nonanomalous preterm infants intrauterine growth retardation is most commonly symmetric and is primarily related to the cumulative number and severity of lesions reflecting abnormal uteroplacental or fetoplacental blood flow. The growth restriction index may contribute to the study of the biologic range of fetal growth. The statistical relationship of most placental lesions to intrauterine growth retardation depends on the presence or absence of preeclampsia.
To determine if placental syncytiotrophoblast microvillous (STBM) membranes contain factors which could cause the maternal endothelial cell disturbance thought to be central to the pathophysiology of the maternal syndrome of pre-eclampsia.
STMB membranes isolated from pre-eclamptic or normal placentae were added to cultures of endothelial cells and their effect on the proliferation (measured by 3H-thymidine incorporation), viability (measured by 51Cr release) and growth as a monolayer of these cells was determined. Membranes prepared from red blood cells, and non-endothelial adherent and nonadherent cell lines were used as specificity controls.
STBM membranes were isolated from the placentae of primigravid women, 10 having caesarean sections for breech presentations and 10 for pre-eclampsia.
STBM membranes from the placentae of normal and pre-eclamptic women suppressed endothelial cell proliferation to a similar extent and disrupted the cell monolayer to form a honeycomb-like pattern. This change in morphology was seen before significant endothelial cell death occurred. Red blood cell membranes had no effect on either endothelial cell proliferation, viability or monolayer integrity. Endothelial cells from human umbilical arteries and bovine adrenal capillaries were similarly suppressed, but comparable concentrations of STBM membranes had no effect on non-endothelial cell lines.
Syncytiotrophoblast microvillous membranes specifically interfered with endothelial cell growth in vitro. Our results demonstrate that there are trophoblast products which could cause the maternal syndrome of pre-eclampsia through endothelial cell damage.
Evidence has been sought for a circulating factor derived from the placenta that suppresses endothelial cell proliferation and hence contributes to the maternal endothelial cell disturbances of preeclampsia.
The effects of sera and plasmas from women with proteinuric preeclampsia and from matched normal pregnant control women on endothelial cell proliferation were compared. The recovery of endothelial cell inhibitory activity from syncytiotrophoblast microvesicles added to male blood and prepared as plasma or serum was determined to investigate the possible placental origin of the inhibitory factor.
Sera from women with preeclampsia did not inhibit endothelial cell proliferation. In contrast, plasma from preeclamptic women significantly suppressed endothelial cell growth at 20% dilution compared with controls, and suppression was more pronounced in severe preeclampsia. The inhibitory activity of syncytiotrophoblast microvesicles added to blood could not be recovered from serum, only from plasma, which may explain why there was no suppression with sera from preeclamptic women.
These results confirm that there is a blood-borne endothelial cell suppressive factor in preeclampsia that may be derived from the placenta.
To investigate whether syncytiotrophoblast microvilli (STBM) are shed into the maternal circulation in increased amounts in pre-eclamptic pregnancies as a possible cause of maternal vascular endothelial dysfunction.
A time-resolved fluoroimmunoassay was developed to measure STBM levels in peripheral and uterine venous plasma from normal pregnant and pre-eclamptic women. Three colour flow cytometry was used to assess the microparticulate nature of the STBM in pregnancy plasma. The effects of these plasmas on endothelial cell proliferation was compared and a correlation with the levels of STBM detected was sought.
A laboratory investigation using clinical samples obtained from an obstetric practice in a teaching hospital.
Peripheral venous plasma from 20 women with established pre-eclampsia, 20 normal pregnant women matched for age, gestation and parity, and 10 nonpregnant women of reproductive age. Paired uterine and peripheral venous plasma taken at caesarean section from 10 women with pre-eclampsia and 10 unmatched normal pregnant women.
STBM were detected in the plasma of pregnant women by both flow cytometry and time-resolved fluoroimmunoassay. Significantly higher levels of STBM were found in women with established pre-eclampsia (P=0.01). STBM concentrations were higher in uterine venous plasma than in concurrently sampled peripheral venous plasma, confirming their placental origin. A significant correlation was found between the amount of STBM in the plasma and endothelial cell inhibitory activity.
STBM are shed into the maternal circulation (microvillous deportation) and are present in significantly increased amounts in pre-eclamptic women. They may contribute to the endothelial dysfunction underlying the maternal syndrome of pre-eclampsia.
Our aim was to seek evidence for circulating leukocyte activation in preeclampsia.
Whole blood flow cytometric techniques were used to analyze surface markers of activation (CD11b, CD14, CD23, CD49d, CD62L, CD64, CD66b, HLA-DR) and intracellular reactive oxygen species. Samples were taken from 21 women with preeclampsia, 21 matched normal pregnant women, 21 healthy nonpregnant controls, and 6 nonpregnant patients with septicemia. Ten preeclamptic cases were followed up 6 weeks post partum.
The leukocytes of healthy pregnant women differed substantially and significantly from those of nonpregnant women (increased CD11b, CD14, and CD64 and increased intracellular reactive oxygen species). In preeclampsia there was, in addition to these changes, reduced expression of L-selectin and further increases in intracellular reactive oxygen species. The changes found in normal pregnancy and preeclampsia were similar, but not identical, to those found in sepsis.
Normal third-trimester pregnancy is characterized by remarkable activation of peripheral blood leukocytes, which is further increased in preeclampsia.
The maternal syndrome of preeclampsia has previously been ascribed to generalized maternal endothelial cell dysfunction. In this review we suggest that the endothelial dysfunction is a part of a more generalized intravascular inflammatory reaction involving intravascular leukocytes as well as the clotting and complement systems. We provide evidence from our recent work and that of others that not only supports this proposal but indicates that such an inflammatory response is already well developed in normal pregnancy and that the differences between normal pregnancy and preeclampsia are less striking than those between the normal pregnant and nonpregnant states. From this we argue that preeclampsia arises when a universal maternal intravascular inflammatory response to pregnancy decompensates in particular cases, which may occur because either the stimulus or the maternal response is too strong. We conclude that there is no specific cause for the disorder, which can be better considered as the extreme end of the range of maternal adaptation to pregnancy. We propose that poor placentation is not the cause of preeclampsia but is a powerful predisposing factor. We predict that a single preeclampsia gene will not be found, nor will either a single specific predictive test or single preventive effective measure be devised. Aspects of the hypothesis are testable, and future work should allow its confirmation or refutation.
There is evidence for both endothelial cell and peripheral blood leukocyte (PBL) activation in pre-eclampsia. Syncytiotrophoblast
microvillous membranes (STBM) are shed in greater quantities from the placenta in pre-eclampsia, disrupt cultured endothelial
cells in vitro and may be the immediate cause of the maternal syndrome. The aim of this study was to determine if endothelial cells co-cultured
with STBM release factors that can activate PBL in vitro. Flow cytometry was used to measure changes in intracellular free ionized calcium ([Ca2+]i), pH (pHi) and reactive oxygen species (iROS) as indices of leukocyte activation. PBL from male non-pregnant donors was exposed to
supernatants from human umbilical vein endothelial cells (HUVEC) cultured with STBM. The time course of changes in [Ca2+]i, pHi and iROS was determined and compared with appropriate control measurements. The test supernatants caused significant activation
of granulocytes and monocytes in terms of increases in [Ca2+]i and falls in pHi and release of iROS. Lymphocytes responded only with respect to increases in iROS. The results define a possible mechanism
for the activation of PBL in pre-eclampsia, as being secondary to endothelial cell activation caused by circulating STBM shed
in excess amounts from the placenta.
The maternal syndrome of pre-eclampsia is thought to result from endothelial cell damage caused by a circulating factor derived from the placenta. This study investigates the hypothesis that trophoblast deportation may be part of the process by which this factor enters the maternal circulation. The nature and incidence of trophoblast deportation was studied in uterine vein and peripheral blood taken from normal and pre-eclamptic women at caesarean section. Trophoblasts were enriched using immunomagnetic beads to deplete leucocytes and labelled with trophoblast-specific monoclonal antibodies. Syncytiotrophoblast, cytotrophoblast, cytotrophoblast clumps and anucleate trophoblast cells were found in uterine vein blood. Cytotrophoblast cells were found to be shed less frequently than syncytiotrophoblast and the majority were probably villous in origin. Trophoblasts were found in the uterine vein blood of normal pregnant women with higher levels in pre-eclampsia. However, trophoblasts were rarely found in the peripheral circulation. There was no correlation between trophoblast numbers and either the severity of the disease, the extent of placental pathology or the inhibitory effect of uterine and peripheral vein plasma on endothelial growth in vitro. Thus, it is speculated that increased trophoblast deportation in pre-eclampsia is secondary to the structural and functional changes occurring in the placenta, rather than directly linked with the circulating endothelial cell damaging factor in pre-eclampsia.
In normal pregnancy there is both a neutrophilia and a mild neutrophil activation. In preeclampsia both direct and indirect evidence supports further marked neutrophil activation. In the pathogenesis of preeclampsia peripheral blood neutrophils may play a vital role in communicating between the preeclamptic placenta and the maternal vascular endothelium and contribute to the endothelial cell dysfunction that characterizes the maternal syndrome of preeclampsia. Preeclampsia shares many elements with the systemic inflammatory response syndrome. Neutrophils, key effectors of the systemic inflammatory response syndrome, are associated with hepatic necrosis and adult respiratory distress syndrome, both of which most commonly kill women with preeclampsia. We hypothesized that delayed neutrophil apoptosis could explain (1) the neutrophilia of normal pregnancy and (2) the differential maternal responses to the shared placental abnormality of preeclampsia and normotensive intrauterine growth restriction.
Neutrophils were isolated (dextran 500, Ficoll [Amersham Pharmacia Biotech AB, Uppsala, Sweden], and erythrocyte lysis) from (1) case patients with preeclampsia at </=34 weeks' gestation, (2) healthy pregnant control subjects, (3) case patients with normotensive intrauterine growth restriction at </=34 weeks' gestation, and (4) nonpregnant female control subjects. Apoptosis was determined after 18 hours of incubation (with or without endotoxin or anti-Fas monoclonal antibody) by deoxyribonucleic acid profile (propidium iodide study), annexin V binding, and CD16 expression.
Compared with propidium iodide profile values in nonpregnant women (median, 25%; range, 14%-40%) neutrophil apoptosis was significantly delayed in normal pregnancy (median, 9.5%; range, 7.6%-15%) and normotensive pregnancy with intrauterine growth restriction (median, 11%; range. 9.3%-19%) and was further delayed in preeclampsia (median, 6.9%; range, 4.1%-8. 2%; P </=.005 vs normal pregnancy and normotensive intrauterine growth restriction). All neutrophils remained sensitive to endotoxin inhibition but were resistant to anti-Fas induction of apoptosis. Spontaneous neutrophil apoptosis decreased as gestational age increased (r (2) = 0.48).
Impaired neutrophil apoptosis may explain the neutrophilia associated with normal pregnancy. In women with preeclampsia activated neutrophils remain in the circulation, perhaps contributing to the persistence of preeclampsia after delivery. Neutrophils appear to modulate the variation in maternal response between preeclampsia and normotensive intrauterine growth restriction.
It has been shown previously that syncytiotrophoblast microvillous membranes (STBM), isolated from normal or pre-eclampsia placentae, specifically inhibit the proliferation of cultured human umbilical vein endothelial cells (HUVEC) and disrupt the cell monolayer without causing cell death. We have previously shown that this anti-proliferative activity resides in a self-aggregating complex in which eight proteins, namely integrins alpha(5)(CD49e) and alpha(V)(CD51), dipeptidyl peptidase IV (DPP IV, CD26), alpha-actinin, transferrin receptor (TfR, CD71), transferrin, placental alkaline phosphatase (PLAP) and monoamine oxidase A (MAO-A) were identified. In the present study, we investigated which of these components causes the anti-proliferative activity of STBM. Antibodies against integrin alpha(5)and alpha(V)and DPP IV all reduced the STBM-induced inhibition of proliferation of HUVEC, which was also reversed by added fibronectin. A preparation of PLAP inhibited endothelial proliferation, but this was not due to enzymatic activity. The preparation was shown to be impure with more than 12 bands present on Coomassie blue stained SDS-PAGE gels. These included integrins alpha(5)and alpha(V), which could account, at least in part, for the inhibitory activity. We could not exclude, however, the possibility of other unidentified factors being involved. We conclude that adhesion molecules account for a major part of the anti-proliferative activity of STBM; these appear to compete for ligands in the extracellular matrix or serum with the appropriate receptors on HUVEC.
To determine whether preeclampsia is associated with an increase in placental apoptosis and differential expression of mediators of apoptosis.
Placental samples from 31 preeclamptic women and 31 normotensive controls were analyzed using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling staining. Expression of Fas, Fas ligand, Bcl-2, and Bax was assessed using immunohistochemistry.
The median percent apoptotic nuclei was significantly higher for the study group than for the controls (0.49 versus 0.19; P =.001), as was the median percent apoptotic nuclei in the trophoblast nuclei (0.33 versus 0.09; P <.01). Fas ligand expression was significantly less and Fas expression significantly greater in the villus trophoblast among the study subjects compared with controls. There was no difference in the expression of Bax or Bcl-2 between groups.
Placental apoptosis and altered expression of Fas and Fas ligand in trophoblast might influence pathogenesis or sequelae of preeclampsia.
This study was undertaken to determine whether preeclampsia and intrauterine growth retardation are associated with an increase in placental apoptosis.
Tissue specimens from 7 normal term placentas and each of 7 term placentas complicated by severe preeclampsia or intrauterine growth retardation were analyzed. Fas antigen and Bcl-2 protein expression were examined by the avidin/biotin immunoperoxidase method, whereas apoptosis was assessed by the terminal deoxynucleotidyl transferase deoxy-UTP-nick end labeling (TUNEL) method and transmission electron microscopy.
Fas antigen was immunolocalized in syncytiotrophoblasts in all placentas examined. No changes in the intensity of Fas antigen immunostaining in syncytiotrophoblasts were apparent among those placentas. Bcl-2 protein was abundantly immunolocalized in syncytiotrophoblasts in normal term placentas, but least abundant in term placentas complicated by severe preeclampsia or intrauterine growth retardation. Apoptosis was apparent in the nuclei of both cytotrophoblasts and syncytiotrophoblasts. The apoptosis positive rate of syncytiotrophoblast nuclei in severe preeclamptic and intrauterine growth retardation term placentas was significantly higher than that in normal term placentas (severe preeclampsia, P <.001; intrauterine growth retardation, P <.01). Transmission electron microscopy revealed the appearance of apoptotic nuclei in trophoblasts in severe preeclamptic term placenta.
Decreased expression of Bcl-2 protein in syncytiotrophoblasts in severe preeclamptic and intrauterine growth retardation placentas may result in the increase in apoptosis in syncytiotrophoblasts in those placentas.
Preeclampsia is a severe disorder of human pregnancy characterized by generalized activation of maternal endothelial cells. Oxidative stress of the placenta is considered a key intermediary step, precipitating deportation of apoptotic fragments into the maternal circulation, but the cause remains unknown. We hypothesize that intermittent placental perfusion, secondary to deficient trophoblast invasion of the endometrial arteries, leads to an ischemia-reperfusion-type insult. We therefore tested whether hypoxia-reoxygenation (H/R) in vitro stimulates apoptosis in human placental tissues compared with controls kept hypoxic or normoxic throughout. After H/R, release of cytochrome c from mitochondria was significantly increased and was associated with intense immunolabeling for active caspase 3 in the syncytiotrophoblast and fetal endothelial cells. There was also increased labeling of syncytiotrophoblastic nuclei for cleaved poly (ADP-ribose) polymerase (PARP), and higher cytosolic concentrations of cleaved PARP fragment were detected by Western blot. Syncytiotrophoblastic nuclei displayed increased chromatin condensation, and a significantly greater percentage was TUNEL positive. These changes were accompanied by increased lactate dehydrogenase release into the medium. Preadministration of the free radical scavenger, desferrioxamine, reduced cytochrome c release and the TUNEL-positive index, suggesting generation of hydroxyl radicals mediates these processes. By contrast, hypoxia alone caused a smaller increase in the TUNEL-positive index, and the majority of syncytiotrophoblastic nuclei displayed karyolysis, whereas normoxic controls remained euchromatic. We conclude that H/R stimulates apoptotic changes within the syncytiotrophoblast, whereas hypoxia principally induces necrosis. The quality of placental perfusion may therefore be a more important factor in the pathophysiology of preeclampsia than the absolute quantity.
The purpose of this study was to characterize gestational profiles of biochemical markers that are associated with preeclampsia in the blood of pregnant women in whom preeclampsia developed later and to compare these markers with the markers of women who were delivered of small-for-gestational-age infants without preeclampsia and with women who were at low risk for the development of preeclampsia.
This was a prospective case control study. The subjects were women at risk of preeclampsia who were enrolled in the placebo arm of a clinical trial. Indices of antioxidant status, oxidative stress, placental and endothelial function, and serum lipid concentrations were evaluated from 20 weeks of gestation until delivery in 21 women in whom preeclampsia developed later, in 17 women without preeclampsia who were delivered of small-for-gestational-age infants, and in 27 women who were at low risk for the development of preeclampsia.
Ascorbic acid was reduced early in preeclampsia and small-for-gestational-age pregnancies. Leptin, placenta growth factor, the plasminogen activator inhibitor (PAI-1)/PAI-2 ratio, and uric acid were predictive of the development of preeclampsia.
Gestational profiles of several markers were abnormal in the group with preeclampsia, and some of the markers that may prove useful in the selective prediction of preeclampsia were identified.
The maternal syndrome of pre-eclampsia is caused by generalized maternal endothelial cell dysfunction, arising directly or indirectly from factors of placental origin. Syncytiotrophoblast membrane microvesicular particles are shed from the placental surface into maternal blood in increased amounts in pre-eclampsia and, in vitro, both inhibit endothelial cell proliferation and cause marked changes in the morphology of the cultured cell monolayers. Because there is evidence that proteolytic activation and degradation of the underlying matrix can cause the same morphological changes, we tested the hypothesis that proteases intrinsic to syncytiotrophoblast microvillous membranes (STBM) are the cause of the in vitro endothelial changes. Purified STBM were analysed by zymography and western blotting. Although we could confirm the presence of urokinase plasminogen activator (uPA) in STBM we could demonstrate no intrinsic activity presumably because of its association with the plasminogen activator inhibitor-2 (PAI-2) which is also a component of STBM. We detected gelatinase activity and showed that it was due to the matrix metalloproteinase-9 (MMP-9). Its presence was confirmed in this location by immunohistocytochemistry. Protease inhibitors caused a small reversal of the effects of STBM on morphology and no effect on inhibition of proliferation. We conclude that the effect of STBM on endothelial cells is unlikely to be caused by intrinsic proteases.
In the third trimester of normal pregnancy, the mother tolerates daily shedding of several grams of dying placental trophoblast into the maternal circulation. The balance between apoptotic and necrotic shedding is presently unknown. Since pre-eclampsia is characterized by an altered placental oxygenation and increased trophoblast shedding, we investigated the role of oxygen on the balance of apoptotic versus necrotic trophoblast shedding in vitro. We studied human trophoblast turnover in explanted villi from late first and third trimester placentas in low oxygen (2 per cent) and higher oxygen tensions (6 per cent and 18 per cent) for up to 72h. Trophoblast turnover including apoptosis and necrosis were assessed by histology, immunolocalization of Mib-1 (proliferation marker), Bcl-2 (apoptosis inhibitor), activated caspase 3 (apoptosis promoter), cytokeratin 18 neo-epitope formation (M30 antibody), TUNEL test (DNA degradation), and (3)H-cytidine and(3) H-uridine incorporations. Culture in 2 per cent oxygen increased cytotrophoblast proliferation and syncytiotrophoblast shedding by necrosis. The proteins necessary for execution of apoptosis were mostly retained in the cytotrophoblast due to lack of syncytial fusion. Culture in 6 per cent and 18 per cent oxygen reduced cytotrophoblast proliferation. Syncytial fusion occurred and activity of caspase 3 was found in the syncytiotrophoblast; the latter remained intact demonstrating physiologic turnover, including apoptotic shedding. We conclude that severe placental hypoxia favours necrotic rather than apoptotic shedding of syncytial fragments into the maternal circulation. Since uteroplacental ischaemia is a significant risk factor for pre-eclampsia, these findings may explain the link between reduced uteroplacental blood flow and the systemic clinical manifestations of this disease.
This paper considers both monocytes and peripheral blood lymphocytes as potential targets for maternal immunological modulation in pregnancy. Peripheral blood mononuclear cells (PBMCs) from non-pregnant and normal pregnant donors were stimulated in vitro, and cytokine production detected intracellularly by flow cytometry. It was found that monocyte production of TNF-alpha was unaltered in pregnancy, while production of IL-12 was significantly enhanced. In contrast, production of the Th1 type cytokine IFN-gamma was suppressed in the lymphocyte subsets: CD4+ T helper cells and CD56+ NK cells. Production of the Th2 type cytokine IL-4 in CD4+ cells was not significantly altered in pregnancy. These data suggest that the concept that pregnancy is a 'Th2 phenomenon' cannot be generalized to the function of all aspects of maternal cellular immunity as, paradoxically, circulating monocytes are 'primed' to produce the Th1 cytokine IL-12. Furthermore, these data support the hypothesis that components of maternal innate immunity are activated in normal pregnancy.
The origins of pre-eclampsia/eclampsia lie in a mismatch between feto-placental demands and utero-placental supply, a situation that also arises in normotensive intrauterine growth restriction (IUGR). Could reactivated chronic infection be both a trigger for these differential maternal responses to the same underlying pathology and a link between pre-eclampsia and its attendant lifelong risks of atherosclerosis?
Nested case-control study.
Tertiary obstetric centre.
Cases of pre-eclampsia, normotensive IUGR and controls.
A nested case-control study of serum from a population-based bank was performed. Seroprevalence and levels of anti-cytomegalovirus (CMV) and Chlamydophila pneumoniae immunoglobulin G (IgG) were compared (non-parametrically) between women with early onset pre-eclampsia (<34 weeks of gestation, n = 9), late onset pre-eclampsia (> or =34 + 0 weeks of gestation, n = 29), normotensive IUGR (birthweight less than third centile, n = 33) and matched normal pregnancy (n = 113, up to 2 per case).
There was a significant difference in both anti-CMV and Chl. pneumoniae antibodies between groups (Kruskal-Wallis test, P < 0.05). Women with early onset pre-eclampsia had higher anti-CMV levels (median: 79, 95% confidence interval [95% CI] = 47, 164) than women with late onset pre-eclampsia (26 [95% CI = 22, 82], P < 0.05), normotensive IUGR (40 [95% CI = 31, 72], P < 0.05) and normal pregnancy (49 [95% CI = 45, 70], P < 0.05). Women with normotensive IUGR had significantly lower anti-Chl. pneumoniae antibodies (0.10 [95% CI = 0.08, 0.38]) than did normal pregnancy controls (0.21 [95% CI = 0.20, 0.28], P <0.05).
The anti-CMV and anti-Chl. pneumoniae antibodies were higher in early onset pre-eclampsia than in late onset pre-eclampsia, normotensive IUGR and normal pregnancy. This may provide a pathophysiological link between pre-eclampsia and the known increased risk for subsequent atherosclerosis.
We have proposed that the maternal syndrome of pre-eclampsia is caused by a systemic inflammatory response involving both leucocytes and endothelium. This inflammatory response is present also in normal pregnancy, but in a milder form. The inflammatory stimulus is most likely to come from the placenta. Syncytiotrophoblast apoptotic debris, which is shed into the maternal circulation in normal pregnancy and in increased amounts in pre-eclampsia, may be the stimulus for this response. It may also contribute to the suppression of Th1 responses seen in pregnancy.
The aim of this study was to quantify placental morphology in pregnancies complicated by pre-eclampsia with and without intrauterine growth restriction. Particular attention is given to the dimensions and composition of peripheral (intermediate+terminal) villi. Placentae from 9 control pregnancies, 5 cases of pre-eclampsia, 5 cases of intrauterine growth restriction and 5 cases of pre-eclampsia with intrauterine growth restriction were randomly sampled for location and position. Formalin-fixed, wax-embedded sections stained by the Masson trichrome method were subjected to stereological analysis in order to quantify the volumes of placental components and the surfaces and derived diameters for peripheral villi and fetal capillaries. Group comparisons were drawn using two-way analysis of variance. Fetal weights were reduced in all complicated pregnancies but only intrauterine growth restriction was accompanied by a significantly smaller placenta. Pre-eclampsia was not associated with main effects on placental morphology and (except for trophoblast thickness) there were no interaction effects involving pre-eclampsia. In contrast, intrauterine growth restriction was associated with a placenta which had reduced volumes of intervillous space and all types of villi (stem, intermediate, terminal). The impoverished growth of peripheral villi affected all tissues (trophoblast, stroma, capillaries) and was accompanied by smaller exchange surface areas and a thicker trophoblastic epithelium. The derived mean diameters of villi and capillaries were not affected. It is concluded that intrauterine growth restriction, but not pre-eclampsia, is associated with substantial changes in placental morphology including impoverished growth of villi and fetal vasculature. These changes are likely to reduce placental oxygen diffusive conductances and contribute to fetal hypoxic stress.
Villous trophoblast is the epithelial cover of the placental villous tree and comes in direct contact with maternal blood. The turnover of villous trophoblast includes proliferation and differentiation of cytotrophoblast, syncytial fusion of cytotrophoblast with the overlying syncytiotrophoblast, differentiation in the syncytiotrophoblast, and finally extrusion of apoptotic material into the maternal circulation. In recent years, it has become clear that apoptosis is a normal constituent of trophoblast turnover and the release of apoptotic material does not lead to an inflammatory response of the mother. During preeclampsia there seems to be an altered balance between proliferation and apoptosis of villous trophoblast leading to a dysregulation of the release from the syncytiotrophoblast. The normal apoptotic release may be reduced in favor of a necrotic release. Since apoptosis is still ongoing in the syncytiotrophoblast, a necrotic release of intrasyncytial and partly apoptotic material lead us to call this type of release "aponecrotic shedding." In this situation, cell-free components such as G-actin and DNA freely floating in maternal blood may trigger damage to the maternal endothelium, thereby triggering preeclampsia. This review highlights the importance of the apoptosis cascade in permitting normal physiologic turnover of villous trophoblast. It will demonstrate the participation of initial stages of this cascade within the cytotrophoblast and of the execution stages within the syncytiotrophoblast. Moreover, this review presents hypotheses of how dysregulation of the apoptosis cascade may be linked to endothelial dysfunction of the maternal vasculature in preeclampsia.
The purpose of this study was to use visual image analysis to observe changes in the morphology and composition of placental villi in pregnancies complicated by preeclampsia (PE) and intrauterine growth restriction (IUGR).
Placental biopsies from nine normal pregnancies, five cases of PE, five cases of IUGR, and five cases of PE with IUGR (PE x IUGR) were randomly sampled. Formalin-fixed, wax-embedded sections were stained with hematoxylin and eosin (H&E) and subjected to image analysis. The placental areas occupied by villi, syncytiotrophoblast, and syncytial cytoplasm and nuclei were quantified.
Significantly smaller placentas were obtained from growth-restricted pregnancies. PE, with and without IUGR, had no effect on the total area occupied by villi or intervillous space. IUGR alone showed a real and consistent reduction in villous area (56.0 +/- 2.4% vs 43.6 +/- 3.3%, P <.03). While the ratio of syncytial to villous areas were noticeably reduced in all cases of PE (0.38 +/- 0.03 vs 0.24 +/- 0.07, P <.05), this ratio remained unchanging in IUGR. Birth weight was positively correlated to both placental size and total villous area occupied. Moreover, increasingly positive relationships were recorded between both syncytiotrophoblast area and syncytiotrophoblast cytoplasm and birth weight (P <.01 and P <.001, respectively).
These measurements point to impoverished villus development in idiopathic IUGR. The observed changes in PE with IUGR were more akin to PE without growth restriction than IUGR alone. This suggests that idiopathic IUGR and IUGR in PE have a separate etiology, idiopathic IUGR arising through a reduction in villous area alone, and IUGR in PE caused by changes in syncytiotrophoblast quantity, more specifically the amount of syncytiotrophoblast cytoplasm.
Intrauterine growth restriction in infants of less than thirty-two weeks' gestation: associated placental pathologic findings Placental debris, oxidative stress and preeclampsia
- Cm Salafia
- Vk Minor
- Jc Pezzullo
- Ej Popek
- Ts Rosenkrantz
- Vintzileos
Salafia CM, Minor VK, Pezzullo JC, Popek EJ, Rosenkrantz TS, Vintzileos AM. Intrauterine growth restriction in infants of less than thirty-two weeks' gestation: associated placental pathologic findings. Am J Obstet Gynecol 1995;173:1049e57. [17] Redman CWG, Sargent IL. Placental debris, oxidative stress and preeclampsia. Placenta 2000;21:597e602.
Shedding of syncytiotrophoblast microvilli into the maternal circulation in pre-eclamptic pregnancies
- Redman M Cwg Knight
- Linton
- Ea
- Sargent
- Il
Knight M, Redman CWG, Linton EA, Sargent IL. Shedding of syncytiotrophoblast microvilli into the maternal circulation in pre-eclamptic pregnancies. Br J Obstet Gynaecol 1998;105:632e40.
Placental debris, oxidative stress and preeclampsia
- Cwg Redman
- Il Sargent
[17] Redman CWG, Sargent IL. Placental debris, oxidative stress and preeclampsia. Placenta 2000;21:597e602.
Shedding of syncytiotrophoblast microvilli into the maternal circulation in pre-eclamptic pregnancies
- Knight