Angiotensin II and angiotensin-(1-7) decrease sFlt1 release in normal but not preeclamptic chorionic villi: an <Emphasis Type="Italic">in vitro</Emphasis> study

Background  

During preeclampsia, placental angiogenesis is impaired. Factors released from the placenta including vascular endothelial growth factor (VEGF), placental growth factor (PLGF), soluble VEGF receptor 1 (sFlt1), and soluble endoglin (sEng) are regulatory molecules of placental development and function. While the renin angiotensin system has been shown to regulate angiogenic factors in other research fields, these mechanisms have not been extensively studied during pregnancy.     

Translational analysis of mouse and human placental protein and mRNA reveals distinct molecular pathologies in human preeclampsia

Preeclampsia (PE) adversely impacts ~5% of pregnancies. Despite extensive research, no consistent biomarkers or cures have emerged, suggesting that different molecular mechanisms may cause clinically similar disease. To address this, we undertook a proteomics study with three main goals: (1) to identify a panel of cell surface markers that distinguish the trophoblast and endothelial cells of the placenta in the mouse; (2) to translate this marker set to human via the Human Protein Atlas database; and (3) to utilize the validated human trophoblast markers to identify subgroups of human preeclampsia. To achieve these goals, plasma membrane proteins at the blood tissue interfaces were extracted from placentas using intravascular silica-bead perfusion, and then identified using shotgun proteomics. We identified 1181 plasma membrane proteins, of which 171 were enriched at the maternal blood-trophoblast interface and 192 at the fetal endothelial interface with a 70% conservation of expression in humans. Three distinct molecular subgroups of human preeclampsia were identified in existing human microarray data by using expression patterns of trophoblast-enriched proteins. Analysis of all misexpressed genes revealed divergent dysfunctions including angiogenesis (subgroup 1), MAPK signaling (subgroup 2), and hormone biosynthesis and metabolism (subgroup 3). Subgroup 2 lacked expected changes in known preeclampsia markers (sFLT1, sENG) and uniquely overexpressed GNA12. In an independent set of 40 banked placental specimens, GNA12 was overexpressed during preeclampsia when co-incident with chronic hypertension. In the current study we used a novel translational analysis to integrate mouse and human trophoblast protein expression with human microarray data. This strategy identified distinct molecular pathologies in human preeclampsia. We conclude that clinically similar preeclampsia patients exhibit divergent placental gene expression profiles thus implicating divergent molecular mechanisms in the origins of this disease.     

ADAM12 and PAPP-A: Candidate regulators of trophoblast invasion and first trimester markers of healthy trophoblasts

ABSTRACT

Proper placental development and function is crucial for a healthy pregnancy, and there has been substantial research to identify markers of placental dysfunction for the early detection of pregnancy complications. Low first-trimester levels of a disintegrin and metalloproteinase 12 (ADAM12) and pregnancy-associated plasma protein-A (PAPP-A) have been consistently associated with the subsequent development of preeclampsia and fetal growth restriction. These molecules are both metalloproteinases secreted by the placenta that cleave insulin-like growth factor binding proteins (IGFBPs), although ADAM12 also has numerous other substrates. Recent work has identified ADAM12, and particularly its shorter variant, ADAM12S, as a regulator of the migration and invasion of trophoblasts into the lining of the uterus, a critical step in normal placental development. While the mechanisms underlying this regulation are not yet clear, they may involve the liberation of heparin-binding EGF-like growth factor (HB-EGF) and/or IGFs from IGFBPs. In contrast, there has been relatively little functional work examining PAPP-A or the IGFBP substrates of ADAM12 and PAPP-A. Understanding the functions of these markers and the mechanisms underlying their association with disease could improve screening strategies and enable the development of new therapeutic interventions.     

Adrenomedullin in perinatal medicine

This review will consider whether adrenomedullin (AM) plays a role in the different aspects of perinatal medicine: contributing to maternal systemic vasodilatation during pregnancy, regulating uterine and placental blood flow, being involved in the process of implantation and participating in uterine quiescence prior to parturition. In addition, this will also consider whether a modification of AM secretion contributes to some pathological conditions in pregnancy such as preeclampsia and impairment of fetal growth. The biosynthesis of AM increases in gravid rats and in pregnant women, and the placenta represents an important site of AM production during pregnancy. Both the peptide and its receptors have been found in the uterus, placenta, fetal membranes and cord vessels, and fetal membranes and placental tissues in culture secrete AM. AM contributes to maternal systemic vasodilatation, the placental vessels are relaxed by AM in a dose-dependent manner and AM is expressed in the fetoplacental and umbilical vascular endothelium where basal production of AM contributes to low fetoplacental vascular resistances. Controversy exists over the status of circulating and placental AM in preeclampsia and of the relative contribution of AM to impaired fetoplacental circulation and fetal growth. Moreover, the uterus expresses AM mRNA and exogenous AM relaxes the myometrium in a dose-dependent manner; however, clinical studies have shown that AM does not decrease before the onset of parturition. Rather, AM secretion increases during spontaneous labor and in preterm delivery.     

Increased levels of serum macrophage colony-stimulating factor before the onset of preeclampsia.

Macrophage colony-stimulating factor (M-CSF) is known to play a central role in maintaining pregnancy. The present study determined whether the increase in serum M-CSF levels preceded the onset of preeclampsia. Blood was collected from 110 normotensive pregnant women at risk for preeclampsia who were carrying single fetuses at about 30 weeks of gestation. After centrifugation, serum was stored at -20 degrees C until assay. Eighteen women developed preeclampsia at a later stage of pregnancy (group 1), while 88 women continued to have normotensive pregnancies until delivery. Thirty-four of the 88 women with normotensive pregnancy who were matched for age and parity were selected to form a control group (group 2). Serum M-CSF levels were determined by the sandwich ELISA method using three antibodies. Serum level of M-CSF was 1,266 U/ml (median) in group 1 and 1,082 U/ml in group 2. Serum M-CSF levels were significantly higher in group 1 than in group 2 (p < 0.0002). Increased levels of serum M-CSF markedly precede the development of clinical manifestations of preeclampsia. High serum M-CSF levels support M-CSF elevation in the placenta. This elevation at 30 weeks of gestation may be associated with placental hypoxia, which is considered the cause of preeclampsia.     

低分子肝素对子痫前期大鼠炎症反应、肝功能及胎盘组织Bcl-2、Bax蛋白表达的影响

目的:研究低分子肝素对子痫前期大鼠炎症反应、肝功能及胎盘组织Bcl-2、Bax蛋白表达的影响.方法:将90只孕期大鼠以随机数表法分成正常孕组、子痫前期组、治疗组,每组30只.其中子痫前期组和治疗组大鼠于妊娠第13 d开始皮下注射左旋硝基精氨酸甲酯,建立子痫前期大鼠模型,注射剂量为200mg/(kg·d),正常孕组予以等...     

Severe feto-placental abnormalities precede the onset of hypertension and proteinuria in a mouse model of preeclampsia

Preeclampsia is a prevalent and potentially devastating disorder of pregnancy. Characterized by a sudden spike in blood pressure and urinary protein levels, it is associated with significant obstetric complications. BPH/5 is an inbred mouse model of preeclampsia with borderline hypertension before pregnancy. BPH/5 mice develop hypertension, proteinuria, and endothelial dysfunction during late gestation (after E14.5). We hypothesized that BPH/5 mice might exhibit early feto-placental abnormalities before the onset of maternal disease. All placental cell lineages were present in BPH/5 mice. However, the fetal and placental weights were reduced, with abnormalities in all the placental zones observed starting early in gestation (E9.5-E12.5). The fractional area occupied by the junctional zone was significantly reduced at all gestational timepoints. Markedly fewer CDKN1C-stained trophoblasts were seen invading the proximal decidual zone, and this was accompanied by reductions in Cdkn1c gene expression. Trophoblast giant cell morphology and cytokeratin staining were not altered, although the mRNA levels of several giant cell-specific markers were significantly downregulated. The labyrinth layer displayed decreased branching morphogenesis of endothelial cells, with electron microscopy evidence of attenuated trophoblast layers. The maternal decidual arteries showed increased wall-to-lumen ratios with persistence of actin-positive smooth muscle cells. These changes translated into dramatically increased vascular resistance in the uterine arteries, as measured by pulse-wave Doppler. Collectively, these results support the hypothesis that defects at the maternal-fetal interface are primary causal events in preeclampsia, and further suggest the BPH/5 model is important for investigations of the underlying pathogenic mechanisms in preeclampsia.     

Neutrophil migration into the placenta: Good,bad or deadly?

ABSTRACT

Almost 2 decades have passed since the discovery that pregnancy is associated with a basal inflammatory state involving neutrophil activation, and that this is more overt in cases with preeclampsia, than in instances with sepsis. This pivotal observation paved the way for our report, made almost a decade ago, describing the first involvement of neutrophil extracellular traps (NETs) in a non-infectious human pathology, namely preeclampsia, where an abundance of these structures were detected directly in the placental intervillous space.

Despite these remarkable findings, there remains a paucity of interest among reproductive biologists in further exploring the role or involvement of neutrophils in pregnancy and related pathologies. In this review we attempt to redress this deficit by highlighting novel recent findings including the discovery of a novel neutrophil subset in the decidua, the interaction of placental protein 13 (PP13) and neutrophils in modulating spiral artery modification, as well as the use of animal model systems to elucidate neutrophil function in implantation, gestation and parturition. These model systems have been particularly useful in identifying key components implicated in recurrent fetal loss, preeclampsia or new signaling molecules such as sphingolipids. Finally, the recent discovery that anti-phospolipid antibodies can trigger NETosis, supports our hypothesis that these structures may contribute to placental dysfunction in pertinent cases with recurrent fetal loss.     

Molecular genetics of preeclampsia and HELLP syndrome — A review

Preeclampsia is characterised by new onset hypertension and proteinuria and is a major obstetrical problem for both mother and foetus. Haemolysis elevated liver enzymes and low platelets (HELLP) syndrome is an obstetrical emergency and most cases occur in the presence of preeclampsia. Preeclampsia and HELLP are complicated syndromes with a wide variety in severity of clinical symptoms and gestational age at onset. The pathophysiology depends not only on periconceptional conditions and the foetal and placental genotype, but also on the capability of the maternal system to deal with pregnancy. Genetically, preeclampsia is a complex disorder and despite numerous efforts no clear mode of inheritance has been established. A minor fraction of HELLP cases is caused by foetal homozygous LCHAD deficiency, but for most cases the genetic background has not been elucidated yet. At least 178 genes have been described in relation to preeclampsia or HELLP syndrome. Confined placental mosaicism (CPM) is documented to cause early onset preeclampsia in some cases; the overall contribution of CPM to the occurrence of preeclampsia has not been adequately investigated yet. This article is part of a Special Issue entitled: Molecular Genetics of Human Reproductive Failure.     

HSP70 expression and its role in preeclamptic stress

Preeclampsia, a hypertensive pregnancy-specific disorder, has long been analyzed for its association with cellular stress. It still remains one of the most serious complications of pregnancy. It is a multi-system disorder that affects maternal vascular function and fetal growth. The physiopathology of preeclampsia is still unclear, but an imbalance between reactive oxygen species (ROS) and antioxidants, appears to be an important contributing factor. Oxidative stress has been increasingly postulated as a major contributor to endothelial dysfunction in preeclampsia (PE). The ROS promotes lipid oxidation and are known to induce stress proteins, such as hemeoxygenase 1 (HO-1) and heat-shock protein 70 (HSP70). Embryonic and placental cells are highly sensitive to oxidative stress due to their proliferate nature. Endothelial cell dysfunction is suggested to be a part of wider maternal inflammatory reaction responsible for the clinical syndrome of preeclampsia. Part of the dysfunction in endothelial cell and trophoblast is attributed to oxidative stress developed during pregnancy. The disequilibrium in compensatory antioxidant control is proposed as a causative mechanism in the pathophysiology of preeclampsia. HSP70 acts as the secondary line of defense in systems with compromised antioxidant function. This article reviews the differential expression of HSP70 and the effect of mint-tea therapy to modulate preeclamptic oxidative damage.     

The Effect of Antenatal Depression and Selective Serotonin Reuptake Inhibitor Treatment on Nerve Growth Factor Signaling in Human Placenta

Depressive symptoms during pregnancy are common and may have impact on the developing child. Selective serotonin reuptake inhibitors (SSRIs) are the most prescribed antidepressant treatment, but unfortunately, these treatments can also negatively affect the behavioral development and health of a child during pregnancy. In addition, serotonin (5-HT) exerts neurotrophic actions with thus far not fully known effects in the offspring. The neurotrophic growth factor (NGF) is involved in neuronal cell survival and differentiation, and altered placenta levels have been found to increase the risk for pregnancy complications, similar to those found in women treated with SSRIs. We therefore investigated whether the NGF signaling pathway was altered in the placenta from women treated with SSRIs (n = 12) and compared them with placenta from depressed (n = 12) and healthy mothers (n = 12). Results from immunohistochemical stainings revealed that placental NGF protein levels of SSRI-treated women were increased in both trophoblasts and endothelial cells compared with depressed and control women. In addition, downstream of the NGF receptor TrkA, increased levels of the signaling proteins ROCK2 and phosphorylated Raf-1 were found in stromal cells and a tendency towards increased levels of ROCK2 in trophoblasts and endothelial cells in SSRI-treated women when compared to healthy controls. SSRI-treated women also displayed increased levels of phosphorylated ROCK2 in all placental cell types studied in comparison with depressed and control women. Interestingly, in placental endothelial cells from depressed women, NGF levels were significantly lower compared to control women, but ROCK2 levels were increased compared with control and SSRI-treated women. Taken together, these results show that the NGF signaling and downstream pathways in the placenta are affected by SSRI treatment and/or antenatal depression. This might lead to an altered placental function, although the clinical relevance of our findings still needs to be investigated.     

Coenzyme Q10 is increased in placenta and cord blood during preeclampsia

Preeclampsia is a common (approximately 7% of all pregnancies) disorder of pregnancy in which the normal hemodynamic response to pregnancy is compromised. Despite many years of intensive research, the pathogenesis of preeclampsia is still not fully understood. The objective of the present study was to investigate the levels of coenzyme Q(10) (CoQ(10)) in placental tissue compared to maternal and umbilical cord levels both during normal pregnancy and in those complicated with preeclampsia. Pregnant women (n = 30) and women with preeclampsia (n = 30) were included. Maternal, newborn cord blood levels and placental content of coenzyme Q(10) were measured by high performance liquid chromatography (HPLC). Plasma coenzyme Q(10) levels were significantly higher in normal pregnant women than in women with preeclampsia. CoQ(10) content in placenta from women with preeclampsia (mean 0.28 SEM 0.11 nmol/mg protein) was significantly higher compared to normal pregnancy (mean 0.09 SEM 0.01 nmol/mg protein; p = 0.05). Levels of CoQ(10) in cord blood from normal pregnant women (mean 0.30 SEM 0.05 micromol/l) were significantly lower than in preeclamptic women (mean 4.03 SEM 2.38 micromol/l). In conclusion, these data indicate a possible involvement of CoQ(10) in preeclampsia that might bear deep physiopathological significance and deserve to be further elucidated.     

Endothelia of term human placentae display diminished expression of tight junction proteins during preeclampsia

This study explores the molecular composition of the tight junction (TJ) in human term placenta from normal women and from patients with preeclampsia, a hypertensive disorder of pregnancy. Maternal endothelial dysfunction is a critical characteristic of preeclampsia; hence, we have analyzed its impact on placental vessels. The study concentrates on the TJ because this structure regulates the sealing of the paracellular route. We have found that, in placental endothelial vessels, TJ components include the peripheral protein ZO–1 and the integral proteins occludin and claudins 1, 3, and 5. During preeclampsia, the amounts of occludin and ZO–1 exhibit no significant variation, whereas those of claudins 1, 3, and 5 diminish, suggesting the presence of leakier TJs in the endothelia of the preeclamptic placenta, possibly in response to the decreased perfusion of this organ during preeclampsia. We have unexpectedly found that, in normal placentae, the multinucleated syncytiotrophoblast layer displays claudin 4 at the basal surface of the plasma membrane, and claudin 16 along the apical and basolateral surfaces. The presence of membrane-lined channels that cross the syncytiotrophoblast constituting a paracellular pathway has been determined by transmission electron microscopy and by the co-immunolocalization of claudin 16 with the plasma membrane proteins Na⁺K⁺-ATPase and GP135. Since claudin 16 functions as a paracellular channel for Mg²⁺, its diffuse pattern in preeclamptic placentae suggests the altered paracellular transport of Mg²⁺ between the maternal blood and the placental tissue.This work was supported by grants 45691-Q from the Mexican Council for Science and Technology (CONACYT) and 2005/1/I/012 from the Research Promotion Fund of the Mexican Institute of Social Security (IMSS/FOFOI).     

Immunohistochemical expression of von Willebrand factor in the preeclamptic placenta

Preeclampsia is a high-prevalence systemic pregnancy disorder associated with maternal and foetal mortality. Its pathogenesis is unknown, but it is thought that oxidative stress and endothelial dysfunction may play a fundamental role. Von Willebrand factor (vWF), a marker of endothelial cell injury, can be found in different cells and zones of the placenta. To determine the differential immunoexpression of vWF at different tissue types of preeclamptic placenta and endothelial dysfunction markers at maternal serum of preeclamptic pregnancies. A case–control study was performed on a population of pregnant women with preeclampsia (n = 14), and normal pregnancies (n = 8). Placental and blood plasma samples were withdrawn at delivery. Immunohistochemical vWF expression in the placental tissue was determined. Endothelial dysfunction was assessed through plasminogen activator inhibitor (PAI) 1 and 2 ratio and vWF concentration in maternal plasma. P values less than 0.05 were considered statistically significant. Preeclamptic women showed increased plasma PAI-1/PAI-2 ratio (P < 0.05). There was diminished placental vWF expression in syncytiotrophoblast and increased in the intervillous space of preeclamptic placentas (P < 0.05). No significant differences in vWF expression were found in the villous endothelium and stroma, but it was significantly higher in maternal plasma (P < 0.05). In preeclampsia occurs endothelial damage and placental cell injury. Cell damage in syncytiotrophoblast that occurs in preeclampsia could liberate vWF from syncytiotrophoblast to the placental intervillous space, and this may have pathogenic implications.     

Diabetes Insipidus in Pregnancy: Etiology,Evaluation, and Management

ObjectiveTo review the approach to a patient with diabetes insipidus during pregnancy.MethodsThis review examines the normal physiology of water homeostasis, the related changes that occur during pregnancy, and the pathophysiology of diabetes insipidus in pregnancy. Associated complications, evaluation, and management are discussed.ResultsDiabetes insipidus can complicate up to 1 in 30000 pregnancies. Diabetes insipidus during pregnancy has a variety of causes, some that predate the pregnancy and others that begin during gestation. Polyuria and polydipsia can occur or be exacerbated in women with overt or subclinical central or nephrogenic diabetes insipidus. These women have either decreased central secretory reserve or impaired renal responsiveness to vasopressin. In addition, women can experience diabetes insipidus de novo in pregnancy through the actions of placental vasopressinase, which causes accelerated degradation of vasopressin. This form of diabetes insipidus may be associated with increased complications of pregnancy, including preeclampsia. Management of central diabetes insipidus and transient diabetes insipidus of pregnancy can be achieved with 1-deamino-8-D-arginine vasopressin (desmopressin acetate) (DDAVP), a vasopressin analogue. Nephrogenic diabetes insipidus is typically resistant to both DDAVP and vasopressin and underlying causes should be addressed.ConclusionsIncreased awareness of diabetes insipidus in pregnancy may lead to early diagnosis and appropriate treatment that will reduce the risks of maternal and fetal morbidity. Overall, growing experience with DDAVP has shown that it is a safe and effective treatment for diabetes insipidus caused by a variety of factors. (Endocr Pract. 2009;15:377-382)     

Preeclampsia‐associated stresses activate Gadd45a signaling and sFlt‐1 in placental explants

Accumulating evidence suggests that placental stresses during pregnancy can play an important role in the pathogenesis of preeclampsia. A common signal pathway that senses and converts placental stresses into intracellular stress response may be contributing to this pathology. Based on our previous findings, we extended our investigation to establish that Gadd45a stress signaling regulates sFlt‐1 levels, particularly in placenta, when exposed to various preeclampsia‐associated stresses including AT‐1 receptor agonist (Angiotensin II), hypoxia, and inflammatory cytokines. Using a placental explant model, we found that Gadd45a was induced in response to all the preeclampsia stresses stated above. Although stress induced Gadd45a was associated with the activation of its downstream effectors phospho‐p38 and phospho‐JNK, the subsequent regulation of sFlt‐1 levels occurred through either one of these effectors, but not both. These observations indicate that Gadd45a signaling may work as a hub connecting placental stresses and the pathogenesis of preeclampsia. It also provides evidence to justify testing the role of Gadd45 in the etiology of preeclampsia using in vivo mouse (i.e., Gadd45a null mice) models. J. Cell. Physiol. 228: 362–370, 2013. © 2012 Wiley Periodicals, Inc.