Plasma concentrations of Lp(a) lipoprotein and TGF-beta1 are altered in preeclampsia

TGFβ signalling: a nexus between inflammation, placental health and preeclampsia throughout pregnancy

BACKGROUND

The placenta is a unique and pivotal organ in reproduction, controlling crucial growth and cell differentiation processes that ensure a successful pregnancy. Placental development is a tightly regulated and dynamic process, in which the transforming growth factor beta (TGFβ) superfamily plays a central role. This family of pleiotropic growth factors is heavily involved in regulating various aspects of reproductive biology, particularly in trophoblast differentiation during the first trimester of pregnancy. TGFβ signalling precisely regulates trophoblast invasion and the cell transition from cytotrophoblasts to extravillous trophoblasts, which is an epithelial-to-mesenchymal transition-like process. Later in pregnancy, TGFβ signalling ensures proper vascularization and angiogenesis in placental endothelial cells. Beyond its role in trophoblasts and endothelial cells, TGFβ signalling contributes to the polarization and function of placental and decidual macrophages by promoting maternal tolerance of the semi-allogeneic foetus. Disturbances in early placental development have been associated with several pregnancy complications, including preeclampsia (PE) which is one of the severe complications. Emerging evidence suggests that TGFβ is involved in the pathogenesis of PE, thereby offering a potential target for intervention in the human placenta.

OBJECTIVE AND RATIONALE

This comprehensive review aims to explore and elucidate the roles of the major members of the TGFβ superfamily, including TGFβs, bone morphogenetic proteins (BMPs), activins, inhibins, nodals, and growth differentiation factors (GDFs), in the context of placental development and function. The review focusses on their interactions within the major cell types of the placenta, namely trophoblasts, endothelial cells, and immune cells, in both normal pregnancies and pregnancies complicated by PE throughout pregnancy.

SEARCH METHODS

A literature search was carried out using PubMed and Google Scholar, searching terms: 'TGF signalling preeclampsia', 'pregnancy TGF signalling', 'preeclampsia tgfβ', 'preeclampsia bmp', 'preeclampsia gdf', 'preeclampsia activin', 'endoglin preeclampsia', 'endoglin pregnancy', 'tgfβ signalling pregnancy', 'bmp signalling pregnancy', 'gdf signalling pregnancy', 'activin signalling pregnancy', 'Hofbauer cell tgfβ signalling', 'placental macrophages tgfβ', 'endothelial cells tgfβ', 'endothelium tgfβ signalling', 'trophoblast invasion tgfβ signalling', 'trophoblast invasion Smad', 'trophoblast invasion bmp', 'trophoblast invasion tgfβ', 'tgfβ preeclampsia', 'tgfβ placental development', 'TGFβ placental function', 'endothelial dysfunction preeclampsia tgfβ signalling', 'vascular remodelling placenta TGFβ', 'inflammation pregnancy tgfβ', 'immune response pregnancy tgfβ', 'immune tolerance pregnancy tgfβ', 'TGFβ pregnancy NK cells', 'bmp pregnancy NK cells', 'bmp pregnancy tregs', 'tgfβ pregnancy tregs', 'TGFβ placenta NK cells', 'TGFβ placenta tregs', 'NK cells preeclampsia', 'Tregs preeclampsia'. Only articles published in English until 2023 were used.

OUTCOMES

A comprehensive understanding of TGFβ signalling and its role in regulating interconnected cell functions of the main placental cell types provides valuable insights into the processes essential for successful placental development and growth of the foetus during pregnancy. By orchestrating trophoblast invasion, vascularization, immune tolerance, and tissue remodelling, TGFβ ligands contribute to the proper functioning of a healthy maternal-foetal interface. However, dysregulation of TGFβ signalling has been implicated in the pathogenesis of PE, where the shallow trophoblast invasion, defective vascular remodelling, decreased uteroplacental perfusion, and endothelial cell and immune dysfunction observed in PE, are all affected by an altered TGFβ signalling.

WIDER IMPLICATIONS

The dysregulation of TGFβ signalling in PE has important implications for research and clinical practice. Further investigation is required to understand the underlying mechanisms, including the role of different ligands and their regulation under pathophysiological conditions, in order to discover new therapeutic targets. Distinguishing between clinically manifested subtypes of PE and studying TGFβ signalling in different placental cell types holistically is an important first step. To put this knowledge into practice, pre-clinical animal models combined with new technologies are needed. This may also lead to improved human research models and identify potential therapeutic targets, ultimately improving outcomes for affected pregnancies and reducing the burden of PE.

MicroRNAs in the Pathogenesis of Preeclampsia-A Case-Control In Silico Analysis

Preeclampsia (PE) occurs in 5% to 7% of all pregnancies, and the PE that results from abnormal placentation acts as a primary cause of maternal and neonatal morbidity and mortality. The objective of this secondary analysis was to elucidate the pathogenesis of PE by probing protein-protein interactions from in silico analysis of transcriptomes between PE and normal placenta from Gene Expression Omnibus (GSE149812). The pathogenesis of PE is apparently determined by associations of miRNA molecules and their target genes and the degree of changes in their expressions with irregularities in the functions of hemostasis, vascular systems, and inflammatory processes at the fetal-maternal interface. These irregularities ultimately lead to impaired placental growth and hypoxic injuries, generally manifesting as placental insufficiency. These differentially expressed miRNAs or genes in placental tissue and/or in blood can serve as novel diagnostic and therapeutic biomarkers.

Effects of calcitriol upon TGF-βs and their receptors in trophoblast cells

Calcitriol levels increase during pregnancy, contributing to the hormonal and immunological balance, but its deficiency has been associated with problems during this period. Meanwhile, transforming growth factors-β (TGF-βs) play an important role in the maintenance of fetal-maternal immune tolerance; however, exacerbated concentrations of this growth factor are associated with complicated pregnancies. Therefore, we studied the effects of calcitriol on TGF-βs and their receptors in trophoblast cells. Term placentas from uncomplicated pregnancies after cesarean sections were used for cell cultures. Basal gene expression and the effect of calcitriol upon TGF-β1, TGF-β2, TGF-β3, and their receptors TGF-βR1 and TGF-βR2 were assessed using real-time PCR from trophoblast cells. The presence of TGF-β1, 2, 3, and TGF-βR1 were evaluated by immunofluorescence, and the protein abundance and secretion of TGF-β1 were assessed by Western blot and ELISA, respectively. Basal gene expression of TGF-β1 in trophoblast from term placentas was higher than TGF-β2 and TGF-β3, while TGF-βR2 was higher than TGF-βR1. The presence and cellular localization of TGF-β1, 2, 3, and TGF-βR1 were detected in the cytoplasm of syncytiotrophoblast, with TGF-β1 showing the highest intensity. Calcitriol significantly inhibited gene expression of TGF-β1, TGF-β2, and TGF-βR1. Likewise, calcitriol decreased the secretion and abundance of TGF-β1. In conclusion, results indicate that calcitriol is a regulator of TGF-βs in cultured trophoblast cells from term placentas and therefore may be an important player in the development of healthy pregnancies.

Roles of TGF-β1 in Viral Infection during Pregnancy: Research Update and Perspectives

Transforming growth factor-beta 1 (TGF-β1) is a pleiotropic growth factor playing various roles in the human body including cell growth and development. More functions of TGF-β1 have been discovered, especially its roles in viral infection. TGF-β1 is abundant at the maternal-fetal interface during pregnancy and plays an important function in immune tolerance, an essential key factor for pregnancy success. It plays some critical roles in viral infection in pregnancy, such as its effects on the infection and replication of human cytomegalovirus in syncytiotrophoblasts. Interestingly, its role in the enhancement of Zika virus (ZIKV) infection and replication in first-trimester trophoblasts has recently been reported. The above up-to-date findings have opened one of the promising approaches to studying the mechanisms of viral infection during pregnancy with links to corresponding congenital syndromes. In this article, we review our current and recent advances in understanding the roles of TGF-β1 in viral infection. Our discussion focuses on viral infection during pregnancy, especially in the first trimester. We highlight the mutual roles of viral infection and TGF-β1 in specific contexts and possible functions of the Smad pathway in viral infection, with a special note on ZIKV infection. In addition, we discuss promising approaches to performing further studies on this topic.

TGF-β1 Promotes Zika Virus Infection in Immortalized Human First-Trimester Trophoblasts via the Smad Pathway

The Zika virus (ZIKV) is well known for causing congenital Zika syndrome if the infection occurs during pregnancy; however, the mechanism by which the virus infects and crosses the placenta barrier has not been completely understood. In pregnancy, TGF-β1 is abundant at the maternal–fetal interface. TGF-β1 has been reported to enhance rubella virus binding and infection in human lung epithelial cells. Therefore, in this study, we investigate the role of TGF-β1 in ZIKV infection in the immortalized human first-trimester trophoblasts, i.e., Swan.71. The cells were treated with TGF-β1 (10 ng/mL) for two days before being inoculated with the virus (American strain PRVABC59) at a multiplicity of infection of five. The results showed an enhancement of ZIKV infection, as demonstrated by the immunofluorescent assay and flow cytometry analysis. Such enhanced infection effects were abolished using SB431542 or SB525334, inhibitors of the TGF-β/Smad signaling pathway. An approximately 2-fold increase in the virus binding to the studied trophoblasts was found. In the presence of the Smad inhibitors, virus replication was significantly suppressed. An enhancement in Tyro3 and AXL (receptors for ZIKV) expression induced by TGF-β1 was also noted. The results suggest that TGF-β1 promotes the virus infection via the Smad pathway. Further studies should be carried out to clarify the underlying mechanisms of these findings.

TGF-β1 inhibits human trophoblast cell invasion by upregulating kisspeptin expression through ERK1/2 but not SMAD signaling pathway

BACKGROUND

Tightly regulation of extravillous cytotrophoblast (EVT) cell invasion is critical for the placentation and establishment of a successful pregnancy. Insufficient EVT cell invasion leads to the development of preeclampsia (PE) which is a leading cause of maternal and perinatal mortality and morbidity. Transforming growth factor-beta1 (TGF-β1) and kisspeptin are expressed in the human placenta and have been shown to inhibit EVT cell invasion. Kisspeptin is a downstream target of TGF-β1 in human breast cancer cells. However, whether kisspeptin is regulated by TGF-β1 and mediates TGF-β1-suppressed human EVT cell invasion remains unclear.

METHODS

The effect of TGF-β1 on kisspeptin expression and the underlying mechanisms were explored by a series of in vitro experiments in a human EVT cell line, HTR-8/SVneo, and primary cultures of human EVT cells. Serum levels of TGF-β1 and kisspeptin in patients with or without PE were measured by ELISA.

RESULTS

TGF-β1 upregulates kisspeptin expression in HTR-8/SVneo cells and primary cultures of human EVT cells. Using pharmacological inhibitor and siRNA, we demonstrate that the stimulatory effect of TGF-β1 on kisspeptin expression is mediated via the ALK5 receptor. Treatment with TGF-β1 activates SMAD2/3 canonical pathways as well as ERK1/2 and PI3K/AKT non-canonical pathways. However, only inhibition of ERK1/2 activation attenuates the stimulatory effect of TGF-β1 on kisspeptin expression. In addition, siRNA-mediated knockdown of kisspeptin attenuated TGF-β1-suppressed EVT cell invasion. Moreover, we report that serum levels of TGF-β1 and kisspeptin are significantly upregulated in patients with PE.

CONCLUSIONS

By illustrating the potential physiological role of TGF-β1 in the regulation of kisspeptin expression, our results may serve to improve current strategies used to treat placental diseases.

Dysregulated BMP2 in the Placenta May Contribute to Early-Onset Preeclampsia by Regulating Human Trophoblast Expression of Extracellular Matrix and Adhesion Molecules

Many pregnancy disorders, including early-onset preeclampsia (EOPE), are associated with defects in placental trophoblast cell invasion and differentiation during early placental development. Bone morphogenetic protein 2 (BMP2) belongs to the TGF-β superfamily and controls various physiological and developmental processes. However, the expression of BMP2 in the placenta and underlying molecular mechanisms of how BMP2 regulates trophoblast function remain unclear. In this study, we analyzed several publicly available microarray and RNA-seq datasets and revealed differences in expression of TGF-β superfamily members between gestational age-matched non-preeclamptic control and EOPE placentas. Importantly, BMP2 levels were significantly reduced in EOPE placentas compared with controls, and RNAscope in situ hybridization further demonstrated BMP2 expression was disrupted in EOPE placental villi. To explore the molecular mechanisms of BMP2-regulated early trophoblast differentiation, we examined BMP2 expression in first-trimester human placenta and found it to be localized to all subtypes of trophoblasts and the decidua. RNA-seq analysis on control and BMP2-treated primary human trophoblast cells identified 431 differentially expressed genes, including several canonical TGF-β/BMP signaling targets (BAMBI, ID1, INHBA, IGFBP3). Gene ontology annotations revealed that differentially expressed genes were involved in cell adhesion and extracellular matrix organization. Furthermore, we identified adhesion molecule with IgG-like domain 2 (AMIGO2) as a novel target for BMP2 that contributed to BMP2-induced trophoblast invasion and endothelial-like tube formation. Overall, our findings provide insight into the molecular processes controlled by BMP2 during early placental development that may contribute to the pathogenesis of EOPE.

Pathogenesis of uteroplacental acute atherosis: An update on current research

Uteroplacental acute atherosis is a type of arterial vascular disease that affects the placenta during pregnancy and predominates in the maternal spiral arteries in the decidua basalis layer of the pregnant uterus. This condition is characterized by fibrin-like necrosis of the blood vessel walls, the accumulation of macrophages containing fat (foam cells), and the infiltration of macrophages around blood vessels. Uteroplacental acute atherosis is rare in normal pregnancy but occurs more frequently in patients with pregnancy complications, including preeclampsia, spontaneous preterm labor, preterm prelabor rupture of membranes, mid-trimester spontaneous abortion, fetal death, and small-for-gestational age. It is believed that the mechanisms underlying the development of uteroplacental acute atherosis are related to the incomplete physiological transformation of spiral arteries, placental inflammation, abnormal lipid metabolism, and oxidative stress. In this review, we describe the pathogenesis of uteroplacental acute atherosis to provide reference guidelines for the future prevention and treatment of uteroplacental acute atherosclerotic disease.

Human Placental NADPH Oxidase Mediates sFlt-1 and PlGF Secretion in Early Pregnancy: Exploration of the TGF-β1/p38 MAPK Pathways

Preeclampsia, a hypertensive disorder occurring during pregnancy, is characterized by excessive oxidative stress and trophoblast dysfunction with dysregulation of soluble Fms-like tyrosine kinase 1 (sFlt-1) and placental growth factor (PlGF) production. Nicotinamide Adenine Dinucleotide Phosphate (NADPH) oxidase (Nox) is the major source of placental superoxide in early pregnancy and its activation with the subsequent formation of superoxide has been demonstrated for various agents including Transforming Growth Factor beta-1 (TGF-β1), a well-known p38 MAPK pathway activator. However, the bridge between Nox and sFlt-1 remains unknown. The purpose of this study was to explore the possible signaling pathway of TGF-β1/Nox/p38 induced sFlt-1 production in human chorionic villi (CV). Methods: Human chorionic villi from first trimester placenta (7–9 Gestational Weeks (GW)) were treated with TGF-β1 or preincubated with p38 inhibitor, SB203580. For NADPH oxidase inhibition, CV were treated with diphenyleneiodonium (DPI). The protein levels of phospho-p38, p38, phospho-Mothers Against Decapentaplegic homolog 2 (SMAD2), and SMAD2 were detected by Western blot. The secretion of sFlt-1 and PlGF by chorionic villi were measured with Electrochemiluminescence Immunologic Assays, and NADPH oxidase activity was monitored by lucigenin method. Results: We demonstrate for the first time that NADPH oxidase is involved in sFlt-1 and PlGF secretion in first trimester chorionic villi. Indeed, the inhibition of Nox by DPI decreases sFlt-1, and increases PlGF secretions. We also demonstrate the involvement of p38 MAPK in sFlt-1 secretion and Nox activation as blocking the p38 MAPK phosphorylation decreases both sFlt-1 secretion and superoxide production. Nevertheless, TGF-β1-mediated p38 activation do not seem to be involved in regulation of the first trimester placental angiogenic balance and no crosstalk was found between SMAD2 and p38 MAPK pathways. Conclusions: Thus, the placental NADPH oxidase play a major role in mediating the signal transduction cascade of sFlt-1 production. Furthermore, we highlight for the first time the involvement of p38 activation in first trimester placental Nox activity.

Cardiac dysfunction after preeclampsia; an overview of pro- and anti-fibrotic circulating effector molecules

Preeclampsia (PE) is strongly associated with heart failure (HF) later in life. The aberrant cardiac remodelling is likely initiated or amplified during preeclamptic pregnancy. Aberrant remodelling often persists after delivery and is known to relate strongly to cardiac fibrosis. This review provides an overview of pro- and anti- fibrotic circulating effector molecules that are involved in cardiac fibrosis and their association with PE. Women with PE complicated pregnancies show increased ANG-II sensitivity and elevated levels of the pro-fibrotic factors IL-6, TNF-α, TGs and FFAs compared to uncomplicated pregnancies. In the postpartum period, PE pregnancies compared to uncomplicated pregnancies have increased ANG-II sensitivity, elevated levels of the pro-fibrotic factors IL-6, TNF-α, LDL cholesterol and leptin, as well as decreased levels of the anti-fibrotic factor adiponectin. The review revealed several profibrotic molecules that associate to cardiac fibrosis during and after PE. The role that these fibrotic factors have on the heart during and after PE may improve the understanding of the link between PE and HF. Furthermore they may provide insight into the pathways in which the relation between both diseases can be understood as potential mechanisms which interfere in the process of cardiovascular disease (CVD). Unravelling the molecular mechanism and pathways involved might bring the diagnostic and therapeutic abilities of those factors a step closer.

The transforming growth factor β superfamily as possible biomarkers of preeclampsia: a comprehensive review

The etiology of preeclampsia - an abnormal placentation-mediated disease - is not fully understood; and there are very few biomarkers with which to predict and diagnose it. Early prediction and diagnosis of this pathology can lead to a significant improvement in maternal and perinatal outcomes. Since members of the transforming growth factor β superfamily influence placentation, and are released from the placenta into the maternal circulatory system, several studies have investigated the involvement of these cytokines in preeclampsia and the possibility of using their serum levels as biomarkers of the disease. In this review, we have summarized the reported relationships between the levels of this superfamily of cytokines and preeclampsia. The available information indicates that altered levels of some of these cytokines are involved in the pathogenesis and pathophysiology of preeclampsia, suggesting their likelihood of serving as predictive and diagnostic biomarkers of the disease.

Transforming Growth Factor Beta 1 Serum Levels in Patients with Preinvasive and Invasive Lesions of the Breast

Transforming growth factor beta (TGF-β)1 is thought to be involved in breast carcinogenesis. TGF-β1 acts in an antiproliferative manner in the early stages of breast carcinogenesis, but promotes tumor progression and metastases in the advanced stages of the disease. No data have been published on serum TGF-β1 in breast cancer. We investigated TGF-β1 serum levels in patients with breast cancer (n=135), ductal carcinoma in situ (DCIS) I to III (n=67) or fibroadenoma (n=35), and in healthy women (n=40) to determine its value as a differentiation marker between malignant, pre-invasive and benign diseases and as a predictive marker for metastatic spread. Median (range) TGF-β1 serum levels in patients with breast cancer, DCIS I-III or benign breast lesions and in healthy women were 48.8 (18–82.4) pg/mL, 45.3 (26.9–58.3) pg/mL, 47.2 (17.2–80.5) pg/mL and 51.6 (30.9–65.1) pg/mL, respectively (p=0.2). In breast cancer patients TGF-β1 serum levels showed no statistically significant correlation with tumor stage, lymph node involvement, histological grade, estrogen receptor status and progesterone receptor status. Our data fail to indicate any correlation between serum TGF-β1 levels and clinicopathological parameters of breast diseases. Serum TGF-β1 levels do not provide clinical information in addition to established tumor markers.

Epithelial-mesenchymal transition during extravillous trophoblast differentiation

A successful pregnancy depends on the intricate and timely interactions of maternal and fetal cells. Placental extravillous cytotrophoblast invasion involves a cellular transition from an epithelial to mesenchymal phenotype. Villous cytotrophoblasts undergo a partial epithelial to mesenchymal transition (EMT) when differentiating into extravillous cytotrophoblasts and gain the capacity to migrate and invade. This review summarizes our current knowledge regarding known regulators of EMT in the human placenta, including the inducers of EMT, upstream transcription factors that control EMT and the downstream effectors, cell adhesion molecules and their differential expression and functions in pregnancy pathologies, preeclampsia (PE) and fetal growth restriction (FGR). The review also describes the research strategies that were used for the identification of the functional role of EMT targets in vitro. A better understanding of molecular pathways driven by placental EMT and further elucidation of signaling pathways underlying the developmental programs may offer novel strategies of targeted therapy for improving feto-placental growth in placental pathologies including PE and FGR.

Aberrant TGFβ Signaling Contributes to Altered Trophoblast Differentiation in Preeclampsia

TGFβ has been implicated in preeclampsia, but its intracellular signaling via phosphorylated mothers against decapentaplegic (SMADs) and SMAD-independent proteins in the placenta remains elusive. Here we show that TGFβ receptor-regulated SMAD2 was activated (Ser(465/467) phosphorylation) in syncytiotrophoblast and proliferating extravillous trophoblast cells of first-trimester placenta, whereas inhibitory SMAD7 located primarily to cytotrophoblast cells. SMAD2 phosphorylation decreased with advancing gestation, whereas SMAD7 expression increased and shifted to syncytiotrophoblasts toward term. Additionally, we found that the TGFβ SMAD-independent signaling via partitioning defective protein 6 (PARD6)/Smad ubiquitylation regulatory factor was activated at approximately 10-12 weeks of gestation in cytotrophoblast and extravillous trophoblast cells comprising the anchoring column. Placentae from early-onset, but not late-onset, preeclampsia exhibited elevated SMAD2 phosphorylation and SMAD7 levels. Whereas PARD6 expression increased and SMURF1 levels decreased in preeclamptic placentae, their association increased. SMAD2 phosphorylation by TGFβ in villous explants and BeWo cells resulted in a reduction of Glial cell missing-1 (GCM1) and fusogenic protein syncytin-1 while increasing cell cycle regulators cyclin E-1 (CCNE1) and cyclin-dependent kinase 4. SMAD7 abrogated the proliferative effects of TGFβ. CCNE1 levels were increased in preeclamptic placentae, whereas GCM1 was markedly reduced. In addition, TGFβ treatment increased the association of PARD6 and SMURF1 and down-regulated Ras homolog gene family, member A (RHOA) GTPase in JEG3 cells. In a wound assay, TGFβ treatment increased the association of PARD6 and SMURF1 and triggered JEG3 cell migration through increased cellular protrusions. Taken together, our data indicate that TGFβ signaling via both SMAD2/7 and PARD6/SMURF1 pathways plays a role in trophoblast growth and differentiation. Altered SMAD regulation of GCM1 and CCNE1 and aberrant expression/activation of PARD6/SMURF1 may contribute to the pathogenesis of preeclampsia by affecting cellular pathways associated with this disorder.

TGFB1 Functional Gene Polymorphisms (C-509T and T869C) in the Maternal Susceptibility to Pre-eclampsia in South Indian Women

Pre-eclampsia (PE), a pregnancy-specific vascular disorder characterized by hypertension and proteinuria, is hypothesized to be the result of inadequate placental angiogenesis with attendant systemic inflammation. The pleiotropic cytokine, Transforming Growth Factor-β1 (TGF-β1), is considered to be a key candidate gene in the molecular pathogenesis of PE by virtue of its ability to not only regulate angiogenesis and apoptosis of target cells, but also by acting as a master controller of Th1/Th2 cytokine balance and production of the anti-inflammatory peripheral regulatory T cells (FOXP3+ Tregs). Based on this presumption, we screened a total of 469 pregnant women from South India that include 239 patients with PE and 230 healthy controls for the two functional polymorphisms of TGFB1 gene (C-509T and T869C). The genotype frequencies of these two polymorphisms differed significantly between the PE and control groups (P = 0.01 and P = 0.002, for the TGFB1 C-509T and T869C polymorphisms, respectively). Under the over-dominant model, the CT genotype of the TGFB1 C509T polymorphism showed a high protective effect (P = 3e-04), while the TT genotype of the same variant appeared to be the predisposing genotype (P = 0.003). The T-T and C-C haplotypes were found to be the risk haplotypes blocks towards PE (OR = 4.72; P = 0.031, OR = 5.39; P = 0.03), respectively. Strong linkage disequilibrium was seen between the two polymorphisms. Our investigations revealed a significant influence of TGFB1 C-509T and T869C polymorphisms on the PE risk in South Indian women. The study represents one of the first of its kind from the Indian subcontinent.

Amniotic mesenchymal cells from pre-eclamptic placentae maintain immunomodulatory features as healthy controls

Pre‐eclampsia (PE) is one of the most severe syndromes in human pregnancy, and the underlying mechanisms of PE have yet to be determined. Pre‐eclampsia is characterized by the alteration of the immune system's activation status, an increase in inflammatory Th1/Th17/APC cells, and a decrease in Th2/Treg subsets/cytokines. Moreover, inflammatory infiltrates have been detected in the amniotic membranes of pre‐eclamptic placentae, and to this date limited data are available regarding the role of amniotic membrane cells in PE. Interestingly, we and others have previously shown that human amniotic mesenchymal stromal cells (hAMSC) possess anti‐inflammatory properties towards almost all immune cells described to be altered in PE. In this study we investigated whether the immunomodulatory properties of hAMSC were altered in PE. We performed a comprehensive study of cell phenotype and investigated the in vitro immunomodulatory properties of hAMSC isolated from pre‐eclamptic pregnancies (PE‐hAMSC), comparing them to hAMSC from normal pregnancies (N‐hAMSC). We demonstrate that PE‐hAMSC inhibit CD4/CD8 T‐cell proliferation, suppress Th1/Th2/Th17 polarization, induce Treg and block dendritic cells and M1 differentiation switching them to M2 cells. Notably, PE‐hAMSC generated a more prominent induction of Treg and higher suppression of interferon‐γ when compared to N‐hAMSC, and this was associated with higher transforming growth factor‐β1 secretion and PD‐L2/PD‐L1 expression in PE‐hAMSC. In conclusion, for the first time we demonstrate that there is no intrinsic impairment of the immunomodulatory features of PE‐hAMSC. Our results suggest that amniotic mesenchymal stromal cells do not contribute to the disease, but conversely, could participate in offsetting the inflammatory environment which characterizes PE.

Transforming growth factor beta-1 (TGF-β1) gene single nucleotide polymorphisms (SNPs) and susceptibility to pre-eclampsia in Iranian women: A case-control study

OBJECTIVES

Pre-eclampsia (PE) is a disorder of pregnancy characterized by high blood pressure and proteinuria. Transforming growth factor beta-1 (TGF-β1) is an important replicated PE candidate gene, and few studies have evaluated the direct association of TGF-β polymorphisms and risk to PE. The aim of this study was to investigate the association between three SNPs of TGF-β1 and serum level of this cytokine in PE patients and controls.

DESIGN AND METHODS

In this study the polymorphisms of the TGF-β1 gene at the coding region, and positions 29T→C (Leu 10 Pro), 74G→C (Arg 25 Pro) and 788C→T (Thr 263 Ile) were studied in 123 PE and 120 normal subjects using PCR-restriction fragment length polymorphism PCR-(RFLP) and amplification refractory mutation system (ARMS)-PCR methods. Moreover, serum TGF-β1 was determined by enzyme-linked immunosorbent assay (ELISA) technique.

RESULTS

At positions 74G→C and 29T→C the genotypes and allele frequencies showed no significant differences between PE patients and normal controls (P=0.3 and P=0.5 respectively). While in the case of position 788C→T both genotypes and allele frequencies were significantly different between PE patients and controls (P=0.02). Haplotype analysis on three polymorphic sites showed no significant differences between PE and control individuals (P=0.8). TGC and CGC haplotypes were the most frequent in both studied groups. The mean serum TGF-β1 level was significantly higher (62.73ng/ml) in PE patients compared with pregnant (47.01ng/ml) and non-pregnant (40.68ng/ml) control groups (P=0.0001).

CONCLUSIONS

The results of this study suggest that TGF-β1 gene 788C→T polymorphism is an important factor mediating the casual pathway of preeclampsia.

Transforming growth factor β signaling in uterine development and function

Transforming growth factor β (TGFβ) superfamily is evolutionarily conserved and plays fundamental roles in cell growth and differentiation. Mounting evidence supports its important role in female reproduction and development. TGFBs1-3 are founding members of this growth factor family, however, the in vivo function of TGFβ signaling in the uterus remains poorly defined. By drawing on mouse and human studies as a main source, this review focuses on the recent progress on understanding TGFβ signaling in the uterus. The review also considers the involvement of dysregulated TGFβ signaling in pathological conditions that cause pregnancy loss and fertility problems in women.

Placental gene expression of transforming growth factor beta 1 (TGF-β1) in small for gestational age newborns

OBJECTIVE

The gene expression of transforming growth factor beta-1 (TGF-β1) in human placental samples obtained from pregnancies with small for gestational age fetuses (SGA) was compared to those of normal pregnancies.

METHODS

In 2011 placental samples from 101 pregnancies with SGA and from 140 normal pregnancies were obtained for analysis of TGF-β1 gene expression. Several clinical parameters were also assessed for correlation between genetic and clinical parameters.

RESULTS

There were no significant differences in gene activity of the TGF-β1 gene between the SGA versus normal pregnancy groups (Ln2α: 0.16; p = 0.07). Within the SGA group, no fetal gender-dependent differences were seen in TGF-β1 gene expression (Ln2α: −0.11; p = 0.05). Similarly, no significant differences in gene activity were observed by the degree of severity of SGA as assessed by percentile fetal birth-weight (Ln2α: 0.32; p = 0.06).

CONCLUSION

We found no change in gene expression of TGF-β1 in placental samples obtained from SGA pregnancies versus normal pregnancy suggesting an absence of a direct role of the TGF-β1 gene in the development of SGA. However, the absence of increased gene expression of TGF-β1 in SGA can be conceptualized as a failure to mount a compensatory response in the SGA environment.

Maternal imbalance between pro-angiogenic and anti-angiogenic factors in HIV-infected women with pre-eclampsia

Abstract

Angiogenic imbalance contributes to the development of preeclampsia. We evaluated the protein expression of the proangiogenic placental growth factor (PlGF) and transforming growth factor beta 1 (TGF-β₁) compared with the anti-angiogenic soluble fms-like tyrosine kinase receptor (sFlt1) and soluble endoglin (sEng) in HIV-infected normotensive and pre-eclamptic pregnancies.

Blood was obtained from 110 pregnant women, enrolled in four groups, namely, HIV-negative normotensives (27); HIV-positive normotensives (31); HIV-negative pre-eclamptics (27) and HIV-positive pre-eclamptics (25), and was used to measure PlGF, TGF-β1, sFlt1 and sEng levels.

Increased sFlt1 and sEng levels were associated with the pre-eclamptics (HIV negative and positive) compared with their counterparts. Decreased PlGF levels were observed between the HIV-negative pre-eclamptics versus HIV-negative normotensives, but levels differed significantly (p = 0.02) among the normotensives (HIV negative and positive). TGF-β₁ remained unchanged across all groups. Higher sEng/TGF-β₁ ratios were associated with the pre-eclamptics (HIV negative and positive) compared with their counterparts. This study demonstrated increased sFlt1 and sEng levels in pre-eclamptic compared with normotensive pregnancies, irrespective of the HIV status.

Polymorphisms and plasma level of transforming growth factor-Beta 1 and risk for preeclampsia: a systematic review

BACKGROUND

Transforming growth factor-beta 1 (TGF-β1) is thought to be involved in the pathogenesis of preeclampsia (PE), but the results are inconsistent among studies. This article aims to compile an overview of the studies about the associations of TGF-β 1 polymorphism and plasma level with PE risk and to provide recommendations for future research.

METHODS AND RESULTS

The databases PubMed, Embase and Web of Science were searched up to December 2013. Five studies investigating the associations of four polymorphisms with the risks of PE were involved. A meta-analysis was conducted for the 869T>C polymorphism and PE risk. The results show that genotype TT of 869T>C polymorphism is a protective factor of PE (pooled odds ratio=0.73, 95% CI: 0.56, 0.95). Eight case-control studies reported the plasma level of TGF-β 1. The substantial heterogeneity among studies may be attributed to the differences in the blood sample processing and the TGF-β 1 analysis kits. The results suggest that plasma TGF-β 1 level in the second trimester was significantly lower in the PE group than in the normal pregnancy group, but was significantly higher in the PE group during the third trimester.

CONCLUSIONS

The current results support that the TGF-β 1 869 T>C polymorphism was associated with the risk of PE. However, the number of eligible studies is small and more studies are needed to clarify whether this association can be detected on larger sample sizes and different populations. Owing to the heterogeneity between studies, no conclusion on the association between plasma TGF-β 1 level and PE risk can be drawn from this review. Further studies about the TGF-β 1 levels at different stages of pregnancy and the development of TGF-β 1 assay methodology are required to reveal the role of TGF-β 1 in the pathological development of PE.

Abnormal Lipid levels as a risk factor of eclampsia, study conducted in tertiary care Hospitals of Khyber Pakhtunkhwa Province - Pakistan

Objective: To evaluate abnormal lipid metabolism as a risk factor of eclampsia in pregnant women.

Methods: This cross sectional study was conducted in three tertiary care hospitals of Peshawar. Serum total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), very low density lipoprotein cholesterol (VLDL-C), triglyceride (TG), apolipoprotein A1 (APO-A1), APO-B100, lipoprotein-a (Lpa) were measured in 110 women with eclampsia and compared with 90 healthy pregnant women. Mean lipid levels in cases and controls were compared using student’s t test”.

Results: Mean systolic/diastolic blood pressure, TC, TG, VLDL-C and Lpa levels were significantly higher (p<0.001) in patients compared to control women. Similarly TC: HDL-C, LDL-C: HDL-C and TG: HDL-C ratio in the patients group were significantly higher (p<0.001) and HDL-C: VLDL-C ratio was significantly lower (p<0.001) in the patients as compared to control group. Undesirable cholesterol were noted in 35.8% patients, HDL-C in 50.5%, borderline high concentration of LDL-C in 23.6%, high triglycerides levels in 73.2%, undesirable cholesterol ratio in 52.3% and undesirable LDL-C ratio were noted in 82.1% patients of eclampsia.

Conclusion: Serum lipids were found significantly higher thus early assessment may be helpful in prevention of complications in the eclampsia patients.

Nox4 and redox signaling mediate TGF-β-induced endothelial cell apoptosis and phenotypic switch

Transforming growth factor-β (TGF-β) triggers apoptosis in endothelial cells, while the mechanisms underlying this action are not entirely understood. Using genetic and pharmacological tools, we demonstrated that TGF-β induced a moderate apoptotic response in human cultured endothelial cells, which was dependent upon upregulation of the Nox4 NADPH oxidase and production of reactive oxygen species (ROS). In contrast, we showed that ectopic expression of Nox4 via viral vectors (vNox4) produced an antiapoptotic effect. TGF-β caused ROS-dependent p38 activation, whereas inhibition of p38 blunted TGF-β-induced apoptosis. However, vNox4, but not TGF-β, activated Akt, and inhibition of Akt attenuated the antiapoptotic effect of vNox4. Akt activation induced by vNox4 was accompanied by inactivation of the protein tyrosine phosphatase-1B (PTP1B) function and enhanced vascular endothelial growth factor receptor (VEGFR)-2 phosphorylation. Moreover, we showed that TGF-β enhanced Notch signaling and increased expression of the arterial marker EphrinB2 in a redox-dependent manner. In summary, our results suggest that Nox4 and ROS have pivotal roles in mediating TGF-β-induced endothelial apoptosis and phenotype specification. Redox mechanisms may influence endothelial cell functions by modulating p38, PTP1B/VEGFR/Akt and Notch signaling pathways.

Pro-inflammatory profile of preeclamptic placental mesenchymal stromal cells: new insights into the etiopathogenesis of preeclampsia

The objective of the present study was to evaluate whether placental mesenchymal stromal cells (PDMSCs) derived from normal and preeclamptic (PE) chorionic villous tissue presented differences in their cytokines expression profiles. Moreover, we investigated the effects of conditioned media from normal and PE-PDMSCs on the expression of pro-inflammatory Macrophage migration Inhibitory Factor (MIF), Vascular Endothelial Growth Factor (VEGF), soluble FMS-like tyrosine kinase-1 (sFlt-1) and free β-human Chorionic Gonadotropin (βhCG) by normal term villous explants. This information will help to understand whether anomalies in PE-PDMSCs could cause or contribute to the anomalies typical of preeclampsia.

METHODS

Chorionic villous PDMSCs were isolated from severe preeclamptic (n = 12) and physiological control term (n = 12) placentae. Control and PE-PDMSCs's cytokines expression profiles were determined by Cytokine Array. Control and PE-PDMSCs were plated for 72 h and conditioned media (CM) was collected. Physiological villous explants (n = 48) were treated with control or PE-PDMSCs CM for 72 h and processed for mRNA and protein isolation. MIF, VEGF and sFlt-1 mRNA and protein expression were analyzed by Real Time PCR and Western Blot respectively. Free βhCG was assessed by immunofluorescent.

RESULTS

Cytokine array showed increased release of pro-inflammatory cytokines by PE relative to control PDMSCs. Physiological explants treated with PE-PDMSCs CM showed significantly increased MIF and sFlt-1 expression relative to untreated and control PDMSCs CM explants. Interestingly, both control and PE-PDMSCs media induced VEGF mRNA increase while only normal PDMSCs media promoted VEGF protein accumulation. PE-PDMSCs CM explants released significantly increased amounts of free βhCG relative to normal PDMSCs CM ones.

CONCLUSIONS

Herein, we reported elevated production of pro-inflammatory cytokines by PE-PDMSCs. Importantly, PE PDMSCs induced a PE-like phenotype in physiological villous explants. Our data clearly depict chorionic mesenchymal stromal cells as central players in placental physiopathology, thus opening to new intriguing perspectives for the treatment of human placental-related disorders as preeclampsia.

Cytokines and Growth Factors in Implantation

Implantation failure is the most important rate limiting factor in the success of assisted reproductive techniques like In vitro fertilization–embryo transfer (IVF-ET). Cytokines are multifunctional signaling molecules having an implicit role in the human implantation process. This review focuses on the redundant roles of cytokines during the various stages of implantation. It also indicates that levels of cytokines in biological fluids like serum and follicular fluid obtained during oocyte retrieval might act as determinants of implantation potential of the blastocyst. Thus a holistic, metabolomic approach of analyzing biological fluids may provide a simpler approach to study the hitherto enigmatic process rather than the proteomic and genomic approach.

Spreading endothelial cell dysfunction in response to necrotic trophoblasts. Soluble factors released from endothelial cells that have phagocytosed necrotic shed trophoblasts reduce the proliferation of additional endothelial cells

The pathogenesis of preeclampsia is not clear but the disease is characterised by systemic endothelial cell dysfunction that is considered to be triggered by a placental factor. Necrotic trophoblastic debris that is deported in the maternal blood is one possible placental trigger for preeclampsia. Syncytial knots were first associated with preeclampsia over 100 years ago. However, syncytial knots are very large and most are trapped in the pulmonary capillaries making it difficult to envisage how they could lead to widespread systemic endothelial cell dysfunction. This study was undertaken to examine whether conditioned medium from endothelial cells that have phagocytosed necrotic trophoblastic debris could adversely affect the proliferation or survival of fresh endothelial cells. Trophoblastic cellular debris, harvested from placental explants was added to endothelial cell monolayers directly or after induction of necrosis by freeze-thawing. Conditioned medium from the endothelial cell cultures was exposed to fresh endothelial cells and their proliferation measured by Alamar Blue, and CyQUANTNF cell proliferation assays. Endothelial cell death was examined by a fluorogenic caspase-3 activity assay and LDH release. Conditioned medium from endothelial cells that had phagocytosed necrotic but not apoptotic trophoblastic debris significantly inhibited the proliferation of fresh endothelial cells but did not induce their death. The conditioned medium also reduced cell-surface endoglin expression by fresh endothelial cells. These results confirm that phagocytosis of necrotic trophoblastic debris by endothelial cells results in the secretion of soluble factors that might explain how necrotic trophoblastic debris trapped in the pulmonary capillaries could induce systemic endothelial cell dysfunction.

The role of autocrine TGFbeta1 in endothelial cell activation induced by phagocytosis of necrotic trophoblasts: a possible role in the pathogenesis of pre-eclampsia

Pre-eclampsia is a disorder of pregnancy characterized by hypertension and endothelial cell dysfunction. The causes of pre-eclampsia are unclear but it is proposed that a factor released from the placenta triggers the maternal symptoms. One possible triggering factor is dead trophoblasts that are shed from the placenta, then deported to become trapped in the maternal pulmonary capillaries. It is hypothesized that trophoblasts die by apoptosis in normal pregnancy, but by necrosis in pre-eclampsia. Deported trophoblasts may be phagocytosed by the pulmonary endothelial cells and we have previously shown that phagocytosis of necrotic trophoblasts leads to the activation of endothelial cells, accompanied by the release of interleukin-6 from these cells. However, the mechanistic pathway linking phagocytosis of necrotic trophoblasts and endothelial cell activation is unknown. Here we show that, after phagocytosis of necrotic, but not apoptotic, trophoblasts, endothelial cells secrete TGFbeta1. Using recombinant endoglin to inhibit the function of TGFbeta1 we have shown that the TGFbeta1 does not directly activate endothelial cells but rather it induces endothelial IL-6 secretion. The IL-6 then induces endothelial cell activation. Inhibiting either TGFbeta1 or IL-6 prevented endothelial cell activation in response to phagocytosing necrotic trophoblasts, but inhibiting IL-6 did not prevent secretion of TGFbeta1, confirming the order of signalling. IL-6 also reduced endothelial cell-surface endoglin but increased the amount of soluble endoglin released from placental explants. These interactions between the IL-6 and TGFbeta1 pathways in both the endothelium and placenta may help to regulate the maternal response to deported trophoblasts in pregnancy.

The essential roles of TGFB1 in reproduction

Transforming growth factor beta 1 (TGFB1) is implicated as a key regulator of the development and cyclic remodelling characteristic of reproductive tissues. The physiological significance of TGFB1 in reproductive biology and fertility has been extensively examined in Tgfb1 null mutant mice. Genetic deficiency in TGFB1 causes perturbed functioning of the hypothalamic-pituitary-gonadal axis, inhibiting luteinising hormone (LH) synthesis and leading to downstream effects on testosterone production in males and estrous cycle abnormalities in females. Oocyte developmental incompetence, accompanied by early embryo arrest as well as altered pubertal mammary gland morphogenesis are observed. In addition to LH and testosterone deficiency, male Tgfb1 null mice demonstrate complete inability to mate with females, associated with failure to initiate and/or sustain successful penile intromission or ejaculation. These studies demonstrate the profound significance of TGFB1 in male and female reproductive physiology, and provide a foundation for exploring the significance of this cytokine in human infertility and sexual dysfunction.

The role of growth factors and cytokines during implantation: endocrine and paracrine interactions

Implantation, a critical step for establishing pregnancy, requires molecular and cellular events resulting in uterine growth and differentiation, blastocyst adhesion, invasion, and placental formation. Successful implantation requires a receptive endometrium, a normal and functional embryo at the blastocyst stage, and a synchronized dialogue between maternal and embryonic tissues. In addition to the well-characterized role of sex steroids, the complexity of embryo implantation and placentation is exemplified by the number of cytokines and growth factors with demonstrated roles in these processes. Disturbances in the normal expression and action of these cytokines result in an absolute or partial failure of implantation and abnormal placental formation in mice and human. Members of the gp130 cytokine family, interleukin-11 (IL-11) and leukemia inhibitory factor, the transforming growth factor beta superfamily, the colony-stimulating factors, and the IL-1 and IL-15 systems are crucial molecules for a successful implantation. Chemokines are also important, both in recruiting specific cohorts of leukocytes to the implantation site and in trophoblast trafficking and differentiation. This review provides discussion of the embryonic and uterine factors that are involved in the process of implantation in autocrine, paracrine, and/or juxtacrine manners at the hormonal, cellular, and molecular levels.

Platelet aggregation and TGF-beta(1) plasma levels in pregnant women with preeclampsia

OBJECTIVES

Platelets and transforming growth factor-beta(1) (TGF-beta(1)) are thought to be involved in the pathogenesis of preeclampsia. Our objectives were to determine plasma concentration of TGF-beta(1) in normotensive and preeclamptic women in the third trimester of pregnancy and to evaluate the correlation of TGF-beta(1) plasma levels with platelet count and agonist-induced aggregation capacity.

METHODS

Thirty-three women with preeclampsia were compared with 36 healthy women with uncomplicated pregnancies. Peripheral venous blood samples were obtained, and TGF-beta(1) plasma levels measured by an enzyme-linked immunoassay. Platelet aggregation was induced by the agonist agents adenosine diphosphate (ADP), collagen and epinephrine, and was determined in platelet-rich plasma by aggregometry.

RESULTS

Plasma concentrations of active TGF-beta(1) were significantly higher in preeclamptic women (10.41+/-2.07ng/mL) compared with normotensive pregnant women (7.01+/-3.29ng/mL). Platelet number and platelet agonist-induced aggregation percent were significantly lower in patients with preeclampsia than in healthy pregnant women. A significant correlation was observed between TGF-beta(1) plasma levels and platelet agonist-induced aggregation percent as between plasma levels of TGF-beta(1) and platelet number in preeclamptic patients.

CONCLUSION

The association between impairment in platelet responsiveness and higher levels of TGF-beta(1) in the plasma of patients with preeclampsia suggests that this cytokine may play a role in the pathophysiological events of preeclampsia that are dependent on platelet activation.

Comparison of cell cycle regulatory gene mRNA in three different types of human trophoblasts and effect of transforming growth factor

AIM

Identifying the factors responsible for reducing the proliferation, syncytialization, and invasiveness of trophoblast tissues, as seen with preeclampsia, intrauterine growth restriction, and spontaneous miscarriage, is a current challenge in reproductive biology. These factors, transforming growth factor (TGF)-beta as an example, can work by altering trophoblast differentiation or proliferation. We therefore investigated and compared specific markers of trophoblast proliferation and differentiation in three commonly used trophoblast tissue cell models, and also investigated the influence of TGF-beta on these markers.

METHODS

In this study, we isolated human trophoblasts from first trimester and term placentas, and additionally used human choriocarcinoma cells (JEG-3). Baseline values of human chorionic gonadotropin (hCG) secretion and relative mRNA levels of cell cycle regulators (cyclin E, p21, p27, and p57) were investigated for each cell type. We also investigated the influence of TGF-beta on these parameters.

RESULTS

Quantitative and longitudinal production of hCG differed between the three cell types. Significantly different amounts of cyclin E, p21, p27, and p57 mRNA were demonstrated within each cell type, as well as between all the cell types, throughout the culture time period. Each trophoblast type demonstrated a reduction of hCG secretion in response to TGF-beta. TGF-beta did not show a consistent effect on the cell cycle mRNA of any of the cell types.

CONCLUSION

We were able to characterize and compare the differential production of hCG, as well as the differential expression of cell cycle-associated mRNA of early trophoblasts, term trophoblasts, and choriocarcinoma cells. The production of hCG was altered by TGF-beta, although mRNA levels were not markedly altered by TGF-beta.

Lipoprotein (a) in pregnancy: a critical review of the literature

In this article the literature on lipoprotein (a) during normal pregnancy and pregnancy complicated by preeclampsia or intrauterine growth restriction is reviewed. MEDLINE, from January 1966 to May 2003, was searched to locate relevant articles in English. Additional publications were identified by reviewing references in selected articles. Studies were reviewed by predefined and strict criteria. It appeared that methodology and results of studies on lipoprotein (a) during normal and complicated pregnancy were very diverse. Lipoprotein (a) increased with advancing gestation or remained unaltered during normal pregnancy. Women with preeclampsia had higher, unaltered or lower lipoprotein (a) concentrations as compared to normal pregnant controls. Only few studies were in agreement with most of the review criteria. In conclusion, published studies on lipoprotein (a) in pregnancy differ substantially in the used methods to measure lipoprotein (a), sample size, study design and ethnicity of the study population. Therefore, these studies yielded conflicting results and no unequivocal view on the role of lipoprotein (a) in normal and complicated pregnancy. Recommendations for future studies are amongst others: the use of an apo(a) independent method for measuring Lp(a), inclusion of sufficient numbers of patients, the use of a longitudinal study design when the objective is to study the changes of Lp(a) during pregnancy and selection of a study population that is ethnically representative for the general population.

Human trophoblast function during the implantation process

The implantation process involves complex and synchronized molecular and cellular events between the uterus and the implanting embryo. These events are regulated by paracrine and autocrine factors. Trophoblast invasion and migration through the uterine wall is mediated by molecular and cellular interactions, controlled by the trophoblast and the maternal microenvironment. This review is focused on the molecular constituents of the human trophoblast, their actions and interactions, including interrelations with the uterine endometrium.

Lipoprotein(a) levels in women with pre-eclampsia and in normotensive pregnant women

AIM

To determine if plasma lipoprotein(a) levels are elevated in pre-eclampsia and if so, their association with the severity of the disease.

METHODS

Ninety-one pre-eclamptic (48 mild, 43 severe) and 40 healthy normotensive pregnant women at more than 32 gestational weeks were recruited into study. Plasma levels of lipoprotein(a), lipids, total protein, albumin and fibrinogen were measured in all subjects.

RESULTS

All groups were comparable with respect to maternal age, maternal weight, gravidity and parity. Platelet count, total serum protein and albumin levels were significantly decreased, whereas fibrinogen levels significantly increased in the pre-eclamptic group. There was no difference between the groups with respect to total cholesterol and low-density lipoprotein levels. In the pre-eclampsic group, triglyceride and very-low-density lipoprotein concentrations were significantly higher, whereas high-density lipoprotein levels were significantly lower. No difference in serum lipoprotein(a) levels was found between the three groups.

CONCLUSIONS

No statistically significant difference existed between normotensive pregnant, and pre-eclamptic women, with regard to plasma lipoprotein(a) levels. It is improbable that high serum lipoprotein(a) levels are risk factors for the development of pre-eclampsia; however, elevated triglyceride-rich lipoproteins might cause endothelial damage leading to pre-eclampsia.

The role of lipoprotein (a) in pregnancies complicated by pre-eclampsia

Endothelial cell dysfunction is a key feature of the pathogenesis of pre-eclampsia. The cause of the endothelial cell injury is probably multifactorial, but poor placenta perfusion plays a major role. In pre-eclampsia, characteristic pathological lesions in the placenta are fibrin deposits, acute atherosis and thrombosis. The similarity between the lesions of pre-eclampsia and atherosclerosis has led to speculations of a common pathophysiological pathway. An abnormal lipid profile is known to be strongly associated with atherosclerotic cardiovascular disease and has a direct effect on endothelial function. Abnormal lipid metabolism seems important in the pathogenesis of pre-eclampsia too. An elevated plasma lipoprotein (a) concentration is a known risk factor for atherosclerotic cardiovascular disease. In this paper, we discuss three hypotheses about the mechanisms by which lipoprotein (a) may be associated with pre-eclampsia: 1. Lp(a), as an acute-phase reactant, transporting cholesterol to sites of endothelial damage for reparation, temporarily increases during pregnancy and increases more during a pregnancy complicated by mild to moderate pre-eclampsia as compared to an uncomplicated pregnancy, in response to a greater extend of endothelial injury in pre-eclampsia. After delivery, pre-eclampsia subsides and Lp(a) concentrations return to baseline levels. 2. In cases of severe pre-eclampsia, there is even more extensive endothelial damage and consequently a higher consumption of Lp(a) in reparation of this vascular damage. These women will have lower concentrations of Lp(a). 3. High baseline concentrations of Lp(a), which are genetically determined, may induce or contribute to the development of pre-eclampsia by promoting endothelial dysfunction. In this line of reasoning one would expect to find higher concentrations of Lp(a) in women at risk for developing pre-eclampsia in a future pregnancy or with a history of pre-eclampsia. As discussed above, these women are also at increased risk for future cardiovascular disease as compared to women with a history of normal pregnancy. The pathophysiologic changes associated with cardiovascular disease may also be responsible for the increased incidence of pre-eclampsia in these women.

Oxidizability of apolipoprotein B-containing lipoproteins and serum paraoxonase/arylesterase activities in preeclampsia

OBJECTIVES

Lipoprotein oxidation has been implicated in the pathogenesis of preeclampsia and paraoxonase, an antioxidant enzyme shown to protect lipoproteins from being oxidized. The aim of the present study was to evaluate oxidizability of apolipoprotein B-containing lipoproteins and serum paraoxonase/arylesterase activities in preeclampsia.

DESIGN AND METHODS

Twenty-one women with mild preeclampsia, 21 women with severe preeclampsia, and 20 women with normal uncomplicated pregnancy were included in this study. Serum malondialdehyde (MDA) level, an indicator of lipid peroxidation, was measured by high-performance liquid chromatography (HPLC). The oxidizability of apolipoprotein B-containing lipoproteins was evaluated by copper-induced in vitro peroxidation of the isolated fraction of apolipoprotein B-containing lipoproteins coupled with the thiobarbituric acid-reactive substances assay and expressed as the difference between copper-treated MDA and basal MDA (DeltaMDA). The serum paraoxonase and arylesterase activities were determined spectrophotometrically.

RESULTS

Serum MDA and DeltaMDA levels of apolipoprotein B-containing lipoproteins were significantly higher in both mild and severe preeclampsia groups than in the normal pregnant group. Serum paraoxonase and arylesterase activities were not significantly different among the study groups.

CONCLUSIONS

Enhancement in oxidizability of apolipoprotein B-containing lipoproteins accompanying with dyslipidemia and increased serum MDA levels suggests that those lipoproteins play a role in the pathogenesis of preeclampsia. Further studies are needed to investigate serum paraoxonase activity in women with normal pregnancies and preeclampsia.

The TGF-beta superfamily and its roles in the human ovary and placenta

The transforming growth factor-beta (TGF-beta) superfamily consists of a large group of growth and differentiation factors, such as TGF-betas, activins, inhibins, growth and differentiation factors (GDFs), and bone morphogenetic proteins (BMPs). These molecules act through specific receptor complexes that are composed of type I and type II serine/threonine receptor kinases. The receptor kinases subsequently activate Smad proteins, which then propagate the signals into the nucleus to regulate target gene expression. Several ligands in this family, such as TGF-betas, activins, inhibins, BMP-15, and GDF-9, play important roles in regulating human ovarian functions, including follicle development and maturation. Activin and TGF-beta are also involved in regulating placental development and functions. Abnormal expression or function of these ligands has been found in several pathological conditions. This review summarizes the role of the TGF-beta superfamily in human ovarian and placental regulation and function, and the potential clinical implications.

Maternal plasma levels of cytokines in normal and preeclamptic pregnancies and their relationship with diastolic blood pressure and fibronectin levels

BACKGROUND

To determine the plasma concentrations of placental growth factor (PLGF), vascular endothelial growth factor (VEGF), transforming growth factor-beta1 (TGF-beta1), soluble tumor necrosis factor alpha receptor (sTNFp55), interleukin-2 receptor (IL-2R), and interleukins 6 and 10 (IL-6, IL-10) in normotensive and preeclamptic women, and to evaluate the correlations between these cytokines and the diastolic blood pressure and fibronectin levels.

METHODS

A prospective case-control study. Thirty-five women with preeclampsia were compared with 34 healthy women with uncomplicated pregnancies. Peripheral venous blood samples were obtained and plasma levels of PLGF, VEGF, TGF-beta1, sTNFp55, IL-2R, IL-6 and IL-10 were measured by an enzyme-linked immunoassay and fibronectin by a radial immundiffusion technic.

RESULTS

In preeclampsia PLGF and VEGF levels were significantly lower, and TGF-beta1, sTNFp55, IL-2R, IL-6 and IL-10 levels were significantly higher than in normotensive pregnancy (p < 0.001). The plasma levels of PLGF and VEGF significantly decreased, whereas TGF-beta1, sTNFp55, IL-2R, IL-6 and IL-10 levels significantly increased with the increments in diastolic blood pressure and fibronectin levels (p < 0.001).

CONCLUSIONS

Altered concentrations of various cytokines might explain the shallow placentation and endothelial cell dysfunction described in preeclampsia. The clinical severity of preeclampsia seems to correlate with the severity of the cytokine abnormalities.

TGF beta1 induces multiple independent signals to regulate human trophoblastic differentiation: mechanistic insights

Transforming growth factor-beta 1 (TGF beta1) plays a crucial role in controlling trophoblast growth and invasion. Loss of this key regulatory function provides the pathophysiological basis for several tumors, which are characterized by uncontrolled telomerase activity. We have shown earlier that telomerase activity is negatively regulated during terminal differentiation of human trophoblasts, and that TGF beta1 may be an important factor governing the transcription of human telomerase reverse transcriptase (hTERT) (the catalytic subunit of the telomerase complex) during this process. In the present study, we extend these observations to identify possible functional effectors of TGF beta1-induced loss in telomerase activity during human trophoblastic differentiation. We show that this regulation may involve the suppression of c-Myc and an increased production of Mad1. We also observed a simultaneous increase in the expression of cyclin-dependent-kinase inhibitors, p21, p27, p15 and p16, associated with a loss in expression of Cyclin-A2 and Cyclin-E. Thus, TGF beta1 may induce multiple independent signals to check the proliferative potential of human trophoblastic cells and allow their functional differentiation.

Factors regulating trophoblast migration and invasiveness: possible derangements contributing to pre-eclampsia and fetal injury

Impaired trophoblast invasiveness and spiral arterial remodelling, which results in poor placental perfusion during early pregnancy, is believed to cause fetal injury and growth retardation, and also endothelial cell activation/dysfunction in a susceptible mother, leading to clinical manifestations of pre-eclampsia. This article briefly reviews the regulatory roles of certain locally active factors in trophoblast migration and invasiveness. This background is then used to discuss and debate whether derangements or dysfunction of some of these factors can manifest as early serum markers predictive of the disease, as opposed to the intermediate and late stage markers which may reflect manifestations and consequences of the disease. Of particular significance are the observed derangements in uPA/uPAR/PAI system, IGFBP-1, HGF, HB-EGF and TGFbeta, factors which are known to regulate trophoblast migration and invasiveness in situ. An emphasis is placed on the need for longitudinal studies in order to identify predictive serum markers which may help strategies for prevention or amelioration of fetal injury and pre-eclampsia.

Prenatal screening, epidemiology, diagnosis, and management of preeclampsia

The cause of preeclampsia remains unknown. The disease manifests itself across a broad clinical spectrum from mild to severe, conferring vastly different morbidities and suggesting possibly different disease processes. Oxidative stress, endothelial dysfunction, maternal-fetal immune incompatibility, and abnormal placental implantation are among the suggested causes. The need for a marker or set of markers that allow for definitive diagnosis and assessment of future risk of preeclampsia is tremendous. Ultrasound techniques and several markers have been identified that are increased among patients with preeclampsia, but no test is highly sensitive. In the future, a combination of markers likely will be used to assess risk and, establish the diagnosis, and test treatment strategies. Such an approach would allow for more refined treatment studies of patients who are at highest risk for preeclampsia.

Transforming growth factor-beta 1 does not relate to hypertension in pre-eclampsia

1. Pre-eclampsia is a human disease of pregnancy characterized by high blood pressure, proteinuria and end-organ damage, if severe. Pre-eclampsia is thought to be related to changes in early placental development, with the formation of a shallower than normal placental bed. 2. Transforming growth factor (TGF)-beta1 is a multifunctional fibrogenic growth factor involved in immune regulation that is elevated in some populations with a high risk of hypertensive end-organ disease related to increases in endothelin release. Transforming growth factor-beta1 is also an important factor in placental implantation. Alterations in TGF-beta1 may be related to abnormal placental development in early pregnancy and, thus, are a candidate for the development of hypertension in pre-eclampsia. 3. The aim of the present study was to examine the placental distribution and serum concentration of TGF-beta1 in patients with pre-eclampsia compared with normal pregnancy. 4. Patients with pre-eclampsia (n = 12) were compared with patients with normal pregnancy (n = 14). Transforming growth factor-beta1 was determined by TGF-beta1 Max ELISA (Promega, Madsion, WI, USA) after serum dilution (1/150) and acid activation. Placental distribution was determined by immunostaining with TGF-beta1 (Santa Cruz, Santa Cruz, CA, USA; 20 ng/mL) and the villi and decidual trophoblast were scored for intensity and extent of staining. 5. Patients with pre-eclampsia had a mean gestational age of 36 weeks, whereas those with a normal pregnancy had a mean gestational age of 39.0 +/- 0.4 weeks. There was no difference in TGF-beta1 concentration between the two groups (mean (+/-SEM) 27.1 +/- 1.0 vs 26.4 +/- 0.7 pg/mL for normal pregnancy and pre-eclampsia, respectively; P = 0.73, Mann-Whitney U-test). There was no correlation between systolic or diastolic blood pressure and TGF-beta1 concentration (regression analysis P = 0.4 and 0.2). Immunostaining was absent in the villous trophoblast cells and endovascular and extravillous trophoblast of term placentas. 6. Although TGF-beta1 is present in trophoblast cells in early pregnancy during placental development, TGF-beta1 concentrations were not increased in the placenta at term in pre-eclampsia and there was no correlation between blood pressure and serum TGF-beta1, suggesting that TGF-beta1 does not play a role in the development of late gestation pre-eclampsia and hypertension.