High-Sensitivity Cardiac Troponin I Enhances Preeclampsia Prediction Beyond Maternal Factors and the sFlt-1/PlGF Ratio.

BACKGROUND: Preeclampsia shares numerous risk factors with cardiovascular diseases. Here, we aimed to assess the potential utility of high-sensitivity cardiac troponin I (hs-cTnI) values during pregnancy in predicting preeclampsia occurrence. METHODS: This study measured hs-cTnI levels in 3721 blood samples of 2245 pregnant women from 4 international, prospective cohorts. Three analytical approaches were used: (1) a cross-sectional analysis of all women using a single blood sample, (2) a longitudinal analysis of hs-cTnI trajectories in women with multiple samples, and (3) analyses of prediction models incorporating hs-cTnI, maternal factors, and the sFlt-1 (soluble fms-like tyrosine kinase 1)/PlGF (placental growth factor) ratio. RESULTS: Women with hs-cTnI levels in the upper quarter had higher odds ratios for preeclampsia occurrence compared with women with levels in the lower quarter. Associations were driven by preterm preeclampsia (odds ratio, 5.78 [95% CI, 2.73-12.26]) and remained significant when using hs-cTnI as a continuous variable adjusted for confounders. Between-trimester hs-cTnI trajectories were independent of subsequent preeclampsia occurrence. A prediction model incorporating a practical hs-cTnI level of detection cutoff (≥1.9 pg/mL) alongside maternal factors provided comparable performance with the sFlt-1/PlGF ratio. A comprehensive model including sFlt-1/PlGF, maternal factors, and hs-cTnI provided added value (cross-validated area under the receiver operator characteristic, 0.78 [95% CI, 0.73-0.82]) above the sFlt-1/PlGF ratio alone (cross-validated area under the receiver operator characteristic, 0.70 [95% CI, 0.65-0.76]; P=0.027). As assessed by likelihood ratio tests, the addition of hs-cTnI to each prediction model significantly improved the respective prediction model not incorporating hs-cTnI, particularly for preterm preeclampsia. Net reclassification improvement analyses indicated that incorporating hs-cTnI improved risk prediction predominantly by correctly reclassifying women with subsequent preeclampsia occurrence. CONCLUSIONS: These exploratory findings uncover a potential role for hs-cTnI as a complementary biomarker in the prediction of preeclampsia. After validation in prospective studies, hs-cTnI, alongside maternal factors, may either be considered as a substitute for angiogenic biomarkers in health care systems where they are sparce or unavailable, or as an enhancement to established prediction models using angiogenic markers.

Platelet-derived factors dysregulate placental sphingosine-1-phosphate receptor 2 in human trophoblasts.

RESEARCH QUESTION: Sphingosine-1-phosphate (S1P) is an essential and bioactive sphingolipid with various functions, which acts through five different G-protein-coupled receptors (S1PR1-5). What is the localization of S1PR1-S1PR3 in the human placenta and what is the effect of different flow rates, various oxygen concentrations and platelet-derived factors on the expression profile of S1PR in trophoblasts? DESIGN: Expression dynamics of placental S1PR1-S1PR3 were determined in human first trimester (n = 10), pre-term (n = 9) and term (n = 10) cases. Furthermore, the study investigated the expression of these receptors in different primary cell types isolated from human placenta, verified the findings with publicly available single-cell RNA-Seq data from first trimester and immunostaining of human first trimester and term placentas. The study also tested whether the placental S1PR subtypes are dysregulated in differentiated BeWo cells under different flow rates, different oxygen concentrations or in the presence of platelet-derived factors. RESULTS: Quantitative polymerase chain reaction revealed that S1PR2 is the predominant placental S1PR in the first trimester and reduces towards term (P < 0.0001). S1PR1 and S1PR3 increased from first trimester towards term (P < 0.0001). S1PR1 was localized in endothelial cells, whereas S1PR2 and S1PR3 were predominantly found in villous trophoblasts. Furthermore, S1PR2 was found to be significantly down-regulated in BeWo cells when co-incubated with platelet-derived factors (P = 0.0055). CONCLUSION: This study suggests that the placental S1PR repertoire is differentially expressed across gestation. S1PR2 expression in villous trophoblasts is negatively influenced by platelet-derived factors, which could contribute to down-regulation of placental S1PR2 over time of gestation as platelet presence and activation in the intervillous space increases from the middle of the first trimester onwards.

Placental Transcriptome Profiling in Subtypes of Diabetic Pregnancies Is Strongly Confounded by Fetal Sex.

The placenta is a temporary organ with a unique structure and function to ensure healthy fetal development. Placental dysfunction is involved in pre-eclampsia (PE), fetal growth restriction, preterm birth, and gestational diabetes mellitus (GDM). A diabetic state affects maternal and fetal health and may lead to functional alterations of placental metabolism, inflammation, hypoxia, and weight, amplifying the fetal stress. The placental molecular adaptations to the diabetic environment and the adaptive spatio-temporal consequences to elevated glucose or insulin are largely unknown (2). We aimed to identify gene expression signatures related to the diabetic placental pathology of placentas from women with diabetes mellitus. Human placenta samples (n = 77) consisting of healthy controls, women with either gestational diabetes mellitus (GDM), type 1 or type 2 diabetes, and women with GDM, type 1 or type 2 diabetes and superimposed PE were collected. Interestingly, gene expression differences quantified by total RNA sequencing were mainly driven by fetal sex rather than clinical diagnosis. Association of the principal components with a full set of clinical patient data identified fetal sex as the single main explanatory variable. Accordingly, placentas complicated by type 1 and type 2 diabetes showed only few differentially expressed genes, while possible effects of GDM and diabetic pregnancy complicated by PE were not identifiable in this cohort. We conclude that fetal sex has a prominent effect on the placental transcriptome, dominating and confounding gene expression signatures resulting from diabetes mellitus in settings of well-controlled diabetic disease. Our results support the notion of placenta as a sexual dimorphic organ.

Diabetic pregnancy as a novel risk factor for cardiac dysfunction in the offspring-the heart as a target for fetal programming in rats.

AIMS/HYPOTHESIS: The impact of diabetic pregnancy has been investigated extensively regarding offspring metabolism; however, little is known about the influence on the heart. We aimed to characterise the effects of a diabetic pregnancy on male adult offspring cardiac health after feeding a high-fat diet in an established transgenic rat model. METHODS: We applied our rat model for maternal type 2 diabetes characterised by maternal insulin resistance with hyperglycaemia and hyperinsulinaemia. Diabetes was induced preconceptionally via doxycycline-induced knock down of the insulin receptor in transgenic rats. Male wild-type offspring of diabetic and normoglycaemic pregnancies were raised by foster mothers, followed up into adulthood and subgroups were challenged by a high-fat diet. Cardiac phenotype was assessed by innovative speckle tracking echocardiography, circulating factors, immunohistochemistry and gene expression in the heart. RESULTS: When feeding normal chow, we did not observe differences in cardiac function, gene expression and plasma brain natriuretic peptide between adult diabetic or normoglycaemic offspring. Interestingly, when being fed a high-fat diet, adult offspring of diabetic pregnancy demonstrated decreased global longitudinal (-14.82 ± 0.59 vs -16.60 ± 0.48%) and circumferential strain (-23.40 ± 0.57 vs -26.74 ± 0.34%), increased relative wall thickness (0.53 ± 0.06 vs 0.37 ± 0.02), altered cardiac gene expression, enlarged cardiomyocytes (106.60 ± 4.14 vs 87.94 ± 1.67 µm), an accumulation of immune cells in the heart (10.27 ± 0.30 vs 6.48 ± 0.48 per fov) and higher plasma brain natriuretic peptide levels (0.50 ± 0.12 vs 0.12 ± 0.03 ng/ml) compared with normoglycaemic offspring on a high-fat diet. Blood pressure, urinary albumin, blood glucose and body weight were unaltered between groups on a high-fat diet. CONCLUSIONS/INTERPRETATION: Diabetic pregnancy in rats induces cardiac dysfunction, left ventricular hypertrophy and altered proinflammatory status in adult offspring only after a high-fat diet. A diabetic pregnancy itself was not sufficient to impair myocardial function and gene expression in male offspring later in life. This suggests that a postnatal high-fat diet is important for the development of cardiac dysfunction in rat offspring after diabetic pregnancy. Our data provide evidence that a diabetic pregnancy is a novel cardiac risk factor that becomes relevant when other challenges, such as a high-fat diet, are present.

Preexisting hypertension and pregnancy-induced hypertension reveal molecular differences in placental proteome in rodents.

Preexisting or new onset of hypertension affects pregnancy and is one of the leading causes of maternal and fetal morbidity and mortality. In certain cases, it also leads to long-term maternal cardiovascular complications. The placenta is a key player in the pathogenesis of complicated hypertensive pregnancies, however the pathomechanisms leading to an abnormal placenta are poorly understood. In this study, we compared the placental proteome of two pregnant hypertensive models with their corresponding normotensive controls: a preexisting hypertension pregnancy model (stroke-prone spontaneously hypertensive rats; SHRSP) versus Wistar-Kyoto and the transgenic RAS activated gestational hypertension model (transgenic for human angiotensinogen Sprague-Dawley rats; SD-PE) versus Sprague-Dawley rats, respectively. Label-free proteomics using nano LC-MS/MS was performed for identification and quantification of proteins. Between the two models, we found widespread differences in the expression of placental proteins including those related to hypertension, inflammation, and trophoblast invasion, whereas pathways such as regulation of serine endopeptidase activity, tissue injury response, coagulation, and complement activation were enriched in both models. We present for the first time the placental proteome of SHRSP and SD-PE and provide insight into the molecular make-up of models of hypertensive pregnancy. Our study informs future research into specific preeclampsia and chronic hypertension pregnancy mechanisms and translation of rodent data to the clinic.

Kidney Injury Caused by Preeclamptic Pregnancy Recovers Postpartum in a Transgenic Rat Model.

Preeclampsia (PE) is characterized by the onset of hypertension (≥140/90 mmHg) and presence of proteinuria (>300 mg/L/24 h urine) or other maternal organ dysfunctions. During human PE, renal injuries have been observed. Some studies suggest that women with PE diagnosis have an increased risk to develop renal diseases later in life. However, in human studies PE as a single cause of this development cannot be investigated. Here, we aimed to investigate the effect of PE on postpartum renal damage in an established transgenic PE rat model. Female rats harboring the human-angiotensinogen gene develop a preeclamptic phenotype after mating with male rats harboring the human-renin gene, but are normotensive before and after pregnancy. During pregnancy PE rats developed mild tubular and glomerular changes assessed by histologic analysis, increased gene expression of renal damage markers such as kidney injury marker 1 and connective-tissue growth factor, and albuminuria compared to female wild-type rats (WT). However, four weeks postpartum, most PE-related renal pathologies were absent, including albuminuria and elevated biomarker expression. Only mild enlargement of the glomerular tuft could be detected. Overall, the glomerular and tubular function were affected during pregnancy in the transgenic PE rat. However, almost all these pathologies observed during PE recovered postpartum.

Speckle Tracking Echocardiography: New Ways of Translational Approaches in Preeclampsia to Detect Cardiovascular Dysfunction.

Several studies have shown that women with a preeclamptic pregnancy exhibit an increased risk of cardiovascular disease. However, the underlying molecular mechanisms are unknown. Animal models are essential to investigate the causes of this increased risk and have the ability to assess possible preventive and therapeutic interventions. Using the latest technologies such as speckle tracking echocardiography (STE), it is feasible to map subclinical changes in cardiac diastolic and systolic function as well as structural changes of the maternal heart. The aim of this work is to compare cardiovascular changes in an established transgenic rat model with preeclampsia-like pregnancies with findings from human preeclamptic pregnancies by STE. The same algorithms were used to evaluate and compare the changes in echoes of human and rodents. Parameters of functionality such as global longitudinal strain (animal -23.54 ± 1.82% vs. -13.79 ± 0.57%, human -20.60 ± 0.47% vs. -15.45 ± 1.55%) as well as indications of morphological changes such as relative wall thickness (animal 0.20 ± 0.01 vs. 0.25 ± 0.01, human 0.34 ± 0.01 vs. 0.40 ± 0.02) are significantly altered in both species after preeclamptic pregnancies. Thus, the described rat model simulates the human situation quite well and is a valuable tool for future investigations regarding cardiovascular changes. STE is a unique technique that can be applied in animal models and humans with a high potential to uncover cardiovascular maladaptation and subtle pathologies.

Interleukin-4 supplementation improves the pathophysiology of hypertension in response to placental ischemia in RUPP rats.

Preeclampsia (PE) is characterized by chronic inflammation and elevated agonistic autoantibodies to the angiotensin type 1 receptor (AT1-AA), endothelin-1, and uterine artery resistance index (UARI) during pregnancy. Previous studies report an imbalance among immune cells, with T-helper type 2 (Th2) cells being decreased during PE. We hypothesized that interleukin-4 (IL-4) would increase Th2 cells and improve the pathophysiology in response to placental ischemia during pregnancy. IL-4 (600 ng/day) was administered via osmotic minipump on gestational day 14 to normal pregnant (NP) and reduced uterine perfusion pressure (RUPP) rats. Carotid catheters were inserted, and Doppler ultrasound was performed on gestational day 18. Blood pressure (mean arterial pressure), TNF-α, IL-6, AT1-AA, natural killer cells, Th2 cells, and B cells were measured on gestational day 19. Mean arterial pressure was 97 ± 2 mmHg in NP ( n = 9), 101 ± 3 mmHg in IL-4-treated NP ( n = 14), and 137 ± 4 mmHg in RUPP ( n = 8) rats and improved to 108 ± 3 mmHg in IL-4-treated RUPP rats ( n = 17) ( P < 0.05). UARI was 0.5 ± 0.03 in NP and 0.8 in RUPP rats and normalized to 0.5 in IL-4-treated RUPP rats ( P < 0.05). Plasma nitrate-nitrite levels increased in IL-4-treated RUPP rats, while placental preproendothelin-1 expression, plasma TNF-α and IL-6, and AT1-AA decreased in IL-4-treated RUPP rats compared with untreated RUPP rats ( P < 0.05). Circulating B cells and placental cytolytic natural killer cells decreased after IL-4 administration, while Th2 cells increased in IL-4-treated RUPP compared with untreated RUPP rats. This study illustrates that IL-4 decreased inflammation and improved Th2 numbers in RUPP rats and, ultimately, improved hypertension in response to placental ischemia during pregnancy.

Downregulation of p53 drives autophagy during human trophoblast differentiation.

The placental barrier is crucial for the supply of nutrients and oxygen to the developing fetus and is maintained by differentiation and fusion of mononucleated cytotrophoblasts into the syncytiotrophoblast, a process only partially understood. Here transcriptome and pathway analyses during differentiation and fusion of cultured trophoblasts yielded p53 signaling as negative upstream regulator and indicated an upregulation of autophagy-related genes. We further showed p53 mRNA and protein levels decreased during trophoblast differentiation. Reciprocally, autophagic flux increased and cytoplasmic LC3B-GFP puncta became more abundant, indicating enhanced autophagic activity. In line, in human first trimester placenta p53 protein mainly localized to the cytotrophoblast, while autophagy marker LC3B as well as late autophagic compartments were predominantly detectable in the syncytiotrophoblast. Importantly, ectopic overexpression of p53 reduced levels of LC3B-II, supporting a negative regulatory role on autophagy in differentiating trophoblasts. This was also shown in primary trophoblasts and human first trimester placental explants, where pharmacological stabilization of p53 decreased LC3B-II levels. In summary our data suggest that differentiation-dependent downregulation of p53 is a prerequisite for activating autophagy in the syncytiotrophoblast.

Placental CX3CL1 is Deregulated by Angiotensin II and Contributes to a Pro-Inflammatory Trophoblast-Monocyte Interaction.

CX3CL1, which is a chemokine involved in many aspects of human pregnancy, is a membrane-bound chemokine shed into circulation as a soluble isoform. Placental CX3CL1 is induced by inflammatory cytokines and is upregulated in severe early-onset preeclampsia. In this study, the hypothesis was addressed whether angiotensin II can deregulate placental CX3CL1 expression, and whether CX3CL1 can promote a pro-inflammatory status of monocytes. qPCR analysis of human placenta samples (n = 45) showed stable expression of CX3CL1 and the angiotensin II receptor AGTR1 throughout the first trimester, but did not show a correlation between both or any influence of maternal age, BMI, and gestational age. Angiotensin II incubation of placental explants transiently deregulated CX3CL1 expression, while the angiotensin II receptor antagonist candesartan reversed this effect. Overexpression of recombinant human CX3CL1 in SGHPL-4 trophoblasts increased adhesion of THP-1 monocytes and significantly increased IL8, CCL19, and CCL13 in co-cultures with human primary monocytes. Incubation of primary monocytes with CX3CL1 and subsequent global transcriptome analysis of CD16⁺ subsets revealed 81 upregulated genes, including clusterin, lipocalin-2, and the leptin receptor. Aldosterone synthase, osteopontin, and cortisone reductase were some of the 66 downregulated genes present. These data suggest that maternal angiotensin II levels influence placental CX3CL1 expression, which, in turn, can affect monocyte to trophoblast adhesion. Release of placental CX3CL1 could promote the pro-inflammatory status of the CD16⁺ subset of maternal monocytes.

Disturbed Placental Imprinting in Preeclampsia Leads to Altered Expression of DLX5, a Human-Specific Early Trophoblast Marker.

BACKGROUND: Preeclampsia is a complex and common human-specific pregnancy syndrome associated with placental pathology. The human specificity provides both intellectual and methodological challenges, lacking a robust model system. Given the role of imprinted genes in human placentation and the vulnerability of imprinted genes to loss of imprinting changes, there has been extensive speculation, but no robust evidence, that imprinted genes are involved in preeclampsia. Our study aims to investigate whether disturbed imprinting contributes to preeclampsia. METHODS: We first aimed to confirm that preeclampsia is a disease of the placenta by generating and analyzing genome-wide molecular data on well-characterized patient material. We performed high-throughput transcriptome analyses of multiple placenta samples from healthy controls and patients with preeclampsia. Next, we identified differentially expressed genes in preeclamptic placentas and intersected them with the list of human imprinted genes. We used bioinformatics/statistical analyses to confirm association between imprinting and preeclampsia and to predict biological processes affected in preeclampsia. Validation included epigenetic and cellular assays. In terms of human specificity, we established an in vitro invasion-differentiation trophoblast model. Our comparative phylogenetic analysis involved single-cell transcriptome data of human, macaque, and mouse preimplantation embryogenesis. RESULTS: We found disturbed placental imprinting in preeclampsia and revealed potential candidates, including GATA3 and DLX5, with poorly explored imprinted status and no prior association with preeclampsia. As a result of loss of imprinting, DLX5 was upregulated in 69% of preeclamptic placentas. Levels of DLX5 correlated with classic preeclampsia markers. DLX5 is expressed in human but not in murine trophoblast. The DLX5high phenotype resulted in reduced proliferation, increased metabolism, and endoplasmic reticulum stress-response activation in trophoblasts in vitro. The transcriptional profile of such cells mimics the transcriptome of preeclamptic placentas. Pan-mammalian comparative analysis identified DLX5 as part of the human-specific regulatory network of trophoblast differentiation. CONCLUSIONS: Our analysis provides evidence of a true association among disturbed imprinting, gene expression, and preeclampsia. As a result of disturbed imprinting, the upregulated DLX5 affects trophoblast proliferation. Our in vitro model might fill a vital niche in preeclampsia research. Human-specific regulatory circuitry of DLX5 might help explain certain aspects of preeclampsia.

CD74-Downregulation of Placental Macrophage-Trophoblastic Interactions in Preeclampsia.

RATIONALE: We hypothesized that cluster of differentiation 74 (CD74) downregulation on placental macrophages, leading to altered macrophage-trophoblast interaction, is involved in preeclampsia. OBJECTIVE: Preeclamptic pregnancies feature hypertension, proteinuria, and placental anomalies. Feto-placental macrophages regulate villous trophoblast differentiation during placental development. Disturbance of this well-balanced regulation can lead to pathological pregnancies. METHODS AND RESULTS: We performed whole-genome expression analysis of placental tissue. CD74 was one of the most downregulated genes in placentas from preeclamptic women. By reverse transcriptase-polymerase chain reaction, we confirmed this finding in early-onset (<34 gestational week, n=26) and late-onset (≥34 gestational week, n=24) samples from preeclamptic women, compared with healthy pregnant controls (n=28). CD74 protein levels were analyzed by Western blot and flow cytometry. We identified placental macrophages to express CD74 by immunofluorescence, flow cytometry, and RT-PCR. CD74-positive macrophages were significantly reduced in preeclamptic placentas compared with controls. CD74-silenced macrophages showed that the adhesion molecules ALCAM, ICAM4, and Syndecan-2, as well as macrophage adhesion to trophoblasts were diminished. Naive and activated macrophages lacking CD74 showed a shift toward a proinflammatory signature with an increased secretion of tumor necrosis factor-α, chemokine (C-C motif) ligand 5, and monocyte chemotactic protein-1, when cocultured with trophoblasts compared with control macrophages. Trophoblasts stimulated by these factors express more CYP2J2, sFlt1, TNFα, and IL-8. CD74-knockout mice showed disturbed placental morphology, reduced junctional zone, smaller placentas, and impaired spiral artery remodeling with fetal growth restriction. CONCLUSIONS: CD74 downregulation in placental macrophages is present in preeclampsia. CD74 downregulation leads to altered macrophage activation toward a proinflammatory signature and a disturbed crosstalk with trophoblasts.

Placental-Specific Overexpression of sFlt-1 Alters Trophoblast Differentiation and Nutrient Transporter Expression in an IUGR Mouse Model.

Since it is known that placental overexpression of the human anti-angiogenic molecule sFlt-1, the main candidate in the progression of preeclampsia, lead to intrauterine growth restriction (IUGR) in mice by lentiviral transduction of mouse blastocysts, we hypothesize that sFlt-1 influence placental morphology and physiology resulting in fetal IUGR. We therefore examined the effect of sFlt-1 on placental morphology and physiology at embryonic day 18.5 with histologic and morphometric analyses, transcript analyses, immunoblotting, and methylation studies. Interestingly, placental overexpression of sFlt-1 leads to IUGR in the fetus and results in lower placental weights. Moreover, we observed altered trophoblast differentiation with reduced expression of IGF2, resulting in a smaller placenta, a smaller labyrinth, and the loss of glycogen cells in the junctional zone. Changes in IGF2 are accompanied by small changes in its DNA methylation, whereas overall DNA methylation is unaffected. In addition, the expression of placental nutrient transporters, such as the glucose diffusion channel Cx26, is decreased. In contrast, the expression of the fatty acid transporter CD36 and the cholesterol transporter ABCA1 is significantly increased. In conclusion, placental sFlt-1 overexpression resulted in a reduction in the differentiation of the spongiotrophoblast into glycogen cells. These findings of a reduced exchange area of the labyrinth and glycogen stores, as well as decreased expression of glucose transporter, could contribute to the intrauterine growth restriction phenotype. All of these factors change the intrauterine availability of nutrients. Thus, we speculate that the alterations triggered by increased anti-angiogenesis strongly affect fetal outcome and programming. J. Cell. Biochem. 118: 1316-1329, 2017. © 2016 Wiley Periodicals, Inc.

Placental DAPK1 and autophagy marker LC3B-II are dysregulated by TNF-α in a gestational age-dependent manner.

Autophagy, a cell-survival process responsible for degradation of protein aggregates and damaged organelles, is increasingly recognized as another mechanism essential for human placentation. A substantial body of experiments suggests inflammation and oxidative stress as the underlying stimuli for altered placental autophagy, giving rise to placenta dysfunction and pregnancy pathologies. Here, the hypothesis is tested whether or not pro-inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α are able to influence the expression profile of autophagy genes in human first-trimester villous placenta. Autophagy-focused qPCR arrays identified substantial downregulation of death-associated protein kinase 1 (DAPK1) in first-trimester placental explants in response to IL-6 and TNF-α, respectively. Immunohistochemistry of placental explants detected considerable DAPK1 staining in placental macrophages, villous cytotrophoblasts and less intense in the syncytiotrophoblast. Both immunohistochemistry and Western blot showed decreased DAPK1 protein in TNF-α-treated placental explants compared to control. On cellular level, DAPK1 expression decreased in SGHPL-4 trophoblasts in response to TNF-α. Observed changes in the expression profile of autophagy-related genes were reflected by significantly decreased lipidation of autophagy marker microtubule-associated protein light chain 3 beta (LC3B-II) in first trimester placental explants in response to TNF-α. Analysis of TNF-α-treated term placental explants showed decreased DAPK1 protein, whereas in contrast to first-trimester LC3B expression and lipidation increased. Immunohistochemistry of placental tissues from early-onset preeclampsia (PE) showed less DAPK1 staining, when compared to controls. Accordingly, DAPK1 mRNA and protein were decreased in primary trophoblasts isolated from early-onset PE, while LC3B-I and -II were increased. Results from this study suggest that DAPK1, a regulator of apoptosis, autophagy and programmed necrosis, decreases in human placenta in response to elevated maternal TNF-α, irrespective of gestational age. In contrast, TNF-α differentially regulates levels of autophagy marker LC3B in human placenta over gestation.

Vitamin D supplementation reduces some AT1-AA-induced downstream targets implicated in preeclampsia including hypertension.

Autoantibodies to the ANG II type I receptor (AT1-AA) are associated with preeclampsia (PE). We found that vitamin D supplementation reduced AT1-AA and blood pressure (MAP) in the RUPP rat model of PE. However, it was undetermined whether the decrease in AT1-AA was the mechanism whereby vitamin D lowered MAP or if it were through factors downstream of AT1-AA. Uterine artery resistance index, placental ET-1, and soluble FMS-like tyrosine kinase-1 are increased with AT1-AA-induced hypertension and are considered markers of PE in pregnant women. Therefore, we hypothesized that vitamin D would reduce PE factors during AT1-AA-induced hypertension and could lower blood pressure in a model of hypertension during pregnancy without PE features. Either ANG II (50 ng·kg-1·day) or AT1-AA (1:40) was infused from gestational day (GD) 12-19. vitamin D2 (VD2, 270 IU/day) or vitamin D3 (VD3, 15 IU/day) was administered orally from GD14-GD18. MAP (mmHg) increased in AT1-AA (121 ± 4) and ANG II (113 ± 1)-infused pregnant rats compared with normal pregnant rats (NP) (101 ± 2) but was lower in AT1-AA+VD2 (105 ± 2), AT1-AA+VD3 (109 ± 2), ANG II+VD2 (104 ± 4), and ANG II+VD3 (104 ± 3). VD2 and/or VD3 improved PE features associated with AT1-AA during pregnancy, while ANG II did not induce such features, supporting the hypothesis that AT1-AA induces PE features during pregnancy, and these are improved with vitamin D. In this study, we demonstrate that vitamin D improved many factors associated with PE and reduced blood pressure in a hypertensive model without PE features, indicating that vitamin D could be beneficial for various hypertensive disorders of pregnancy.

Increased apoptosis, altered oxygen signaling, and antioxidant defenses in first-trimester pregnancies with high-resistance uterine artery blood flow.

The mechanisms of deficient placentation in the first trimester remain poorly understood, although apoptosis, hypoxia, and oxidative stress have been implicated. High uterine artery Doppler resistance indexes (RIs) are predictive of placental complications of pregnancy, such as preeclampsia, fetal growth restriction, and stillbirth. We provide evidence that even in the first trimester, pregnancies with high uterine artery Doppler RI demonstrate alterations in placental gene and protein expression. Apoptosis was significantly higher in high RI placental tissue, as determined by Western blot analysis of cleaved poly (ADP-ribose) polymerase and caspase 3. Protein expression of the trophoblast survival factor insulin-like growth factor-2 was significantly lower. Both high and normal RI placentas showed evidence of hypoxia and oxidative stress with expression of hypoxia-inducible factors 1α and 2α, heat shock protein 70, presence of nitrotyrosine residues, and lipid peroxidation. We observed no exaggerated placental hypoxia or oxidative stress associated with high RI pregnancies. High RI placental tissue demonstrated an altered balance of antioxidant enzyme activity. Hypoxia and oxidative stress appear to be a physiological state in early pregnancy; our data did not support the hypothesis that they are associated with deficient placentation in the first trimester. Higher levels of apoptosis, reduced insulin-like growth factor-2 expression, and altered antioxidant defenses may contribute to abnormal placentation and the later development of pregnancy complications, such as preeclampsia, fetal growth restriction, and stillbirth.

Placental fractalkine is up-regulated in severe early-onset preeclampsia.

The pathogenesis of preeclampsia (PE) includes the release of placental factors into the maternal circulation, inducing an inflammatory environment in the mother. One of the factors may be the proinflammatory chemokine fractalkine, which is expressed in the syncytiotrophoblast of human placenta, from where it is released into the maternal circulation by constitutive shedding. We examined whether placental fractalkine is up-regulated in severe early-onset PE and whether the proinflammatory cytokines tumor necrosis factor (TNF)-α and IL-6 are able to increase the expression of fractalkine. Gene expression analysis, enzyme-linked immunosorbent assay, and immunohistochemistry consistently showed increased fractalkine expression in placentas from severe early-onset PE, compared to gestational age-matched controls. Expression of a disintegrin and metalloproteinases (ADAMs) 10 and 17, which convert transmembrane fractalkine into the soluble form, was significantly increased in these cases. Incubation of first-trimester placental explants with TNF-α provoked a significant increase in fractalkine expression and release of the soluble form, whereas IL-6 had no effect. TNF-α-mediated up-regulation of placental fractalkine was reversed in the presence of the aspirin-derivative salicylate, which impaired activation of NF-κB p65 in TNF-α-treated explants. On the basis of data from placental explants, we suggest that increased maternal TNF-α may up-regulate the expression and release of placental fractalkine, which, in turn, may contribute to an exaggerated systemic inflammatory response in PE.

Reduced uterine perfusion pressure T-helper 17 cells cause pathophysiology associated with preeclampsia during pregnancy.

Preeclampsia is associated with chronic inflammation and an imbalance among T-helper cell subtypes with an increase in T-helper 17 (TH17) cells. The objective of this study was to determine a role for TH17s, from the reduced uterine perfusion pressure (RUPP) rat model of preeclampsia, in the etiology of hypertension and chronic inflammation during pregnancy. CD4+/CD25- T cells were isolated from rat spleens, cultured in TH17 media, and were verified as TH17s via flow cytometry. On day 12 of gestation, 1×106 TH17 cells from RUPP rats were adoptively transferred into NP rats, carotid catheters were inserted on day 18, and on day 19, mean arterial pressure (MAP) was recorded, serum and plasma were collected, and oxidative stress and production of agonistic autoantibodies to the ANG II type I receptor (AT1-AA) were analyzed. MAP increased from 100.3 ± 1.7 mmHg in normal pregnant (NP; n = 17) to 124.8 ± 2.1 mmHg in RUPP (n = 22; P < 0.0001) and to 110.8 ± 2.8 mmHg in NP+RUPP TH17 (n = 11). Pup weights in NP+RUPP TH17s were decreased to 1.92 ± 0.09 g from 2.39 ± 0.14 in NP rats (P < 0.01). AT1-AA significantly increased from 0.1 ± 0.2 beats/min in NP to 15.6 ± 0.7 beats/min in NP+RUPP TH17s. IL-6 was 22.3 ± 5.7 pg/ml in NP and increased to 60.45 ± 13.8 pg/ml in RUPP (P < 0.05) and 75.9 ± 6.8 pg/ml in NP+RUPP TH17 rats (P < 0.01). Placental and renal oxidative stress were 238 ± 27.5 and 411 ± 129.9 relative light units·min-1·mg-1 in NP and 339 ± 104.6 and 833 ± 331.1 relative light units·min-1·mg-1 in NP+RUPP TH17, respectively. In conclusion, RUPP TH17 cells induced intrauterine growth restriction and increased blood pressure, AT1-AA, IL-6, and tissue oxidative stress when transferred to NP rats, indicating a role for autoimmune associated TH17 cells, to cause much of the pathophysiology associated with preeclampsia.

Vitamin D supplementation improves pathophysiology in a rat model of preeclampsia.

Deficiency of vitamin D (VD) is associated with preeclampsia (PE), a hypertensive disorder of pregnancy characterized by proinflammatory immune activation. We sought to determine whether VD supplementation would reduce the pathophysiology and hypertension associated with the reduced uterine perfusion pressure (RUPP) rat model of PE. Normal pregnant (NP) and RUPP rats were supplemented with VD2 or VD3 (270 IU and 15 IU/day, respectively) on gestation days 14-18 and mean arterial pressures (MAPs) measured on day 19. MAP increased in RUPP to 123 ± 2 mmHg compared with 102 ± 3 mmHg in NP and decreased to 113 ± 3 mmHg with VD2 and 115 ± 3 mmHg with VD3 in RUPP rats. Circulating CD4+ T cells increased in RUPP to 7.90 ± 1.36% lymphocytes compared with 2.04 ± 0.67% in NP but was lowered to 0.90 ± 0.19% with VD2 and 4.26 ± 1.55% with VD3 in RUPP rats. AT1-AA, measured by chronotropic assay, decreased from 19.5 ± 0.4 bpm in RUPPs to 8.3 ± 0.5 bpm with VD2 and to 15.4 ± 0.7 bpm with VD3. Renal cortex endothelin-1 (ET-1) expression was increased in RUPP rats (11.6 ± 2.1-fold change from NP) and decreased with both VD2 (3.3 ± 1.1-fold) and VD3 (3.1 ± 0.6-fold) supplementation in RUPP rats. Plasma-soluble FMS-like tyrosine kinase-1 (sFlt-1) was also reduced to 74.2 ± 6.6 pg/ml in VD2-treated and 91.0 ± 16.1 pg/ml in VD3-treated RUPP rats compared with 132.7 ± 19.9 pg/ml in RUPP rats. VD treatment reduced CD4+ T cells, AT1-AA, ET-1, sFlt-1, and blood pressure in the RUPP rat model of PE and could be an avenue to improve treatment of hypertension in response to placental ischemia.

Interfering with Gal-1-mediated angiogenesis contributes to the pathogenesis of preeclampsia.

Preeclampsia (PE) is a pregnancy-specific disorder characterized by sudden onset of hypertension and proteinuria in the second half of pregnancy (>20 wk). PE is strongly associated with abnormal placentation and an excessive maternal inflammatory response. Galectin-1 (Gal-1), a member of a family of carbohydrate-binding proteins, has been shown to modulate several processes associated with placentation and to promote maternal tolerance toward fetal antigens. Here, we show that Gal-1 exhibits proangiogenic functions during early stages of pregnancy, promoting decidual vascular expansion through VEGF receptor 2 signaling. Blocking Gal-1-mediated angiogenesis or lectin, galactoside-binding, soluble, 1 deficiency results in a spontaneous PE-like syndrome in mice, mainly by deregulating processes associated with good placentation and maternal spiral artery remodeling. Consistent with these findings, we observed a down-regulation of Gal-1 in patients suffering from early onset PE. Collectively, these results strengthen the notion that Gal-1 is required for healthy gestation and highlight Gal-1 as a valuable biomarker for early PE diagnosis.