Soluble and membranous vascular endothelial growth factor receptor-1 in pregnancies complicated by pre-eclampsia

VEGFR endocytosis: Implications for angiogenesis

The binding of vascular endothelial growth factor (VEGF) superfamily to VEGF receptor tyrosine kinases (VEGFRs) and co-receptors regulates vasculogenesis, angiogenesis and lymphangiogenesis. A recurring theme is that dysfunction in VEGF signaling promotes pathological angiogenesis, an important feature of cancer and pro-inflammatory disease states. Endocytosis of basal (resting) or activated VEGFRs facilitates signal attenuation and endothelial quiescence. However, increasing evidence suggest that activated VEGFRs can continue to signal from intracellular compartments such as endosomes. In this chapter, we focus on the evolving link between VEGFR endocytosis, signaling and turnover and the implications for angiogenesis. There is much interest in how such understanding of VEGFR dynamics can be harnessed therapeutically for a wide range of human disease states.

Placental lesions and differential expression of pro-and anti-angiogenic growth mediators and oxidative DNA damage marker in placentae of Ghanaian suboptimal and optimal health status pregnant women who later developed preeclampsia

Background

Angiogenic growth mediators (AGMs) and oxidative stress (OS) both play essential roles in normal placental vascular development and as such, placental alterations in these factors contribute to pre-eclampsia (PE). Suboptimal health status (SHS), an intermediate between health and disease, has been associated with imbalanced AGMs and OS biomarkers. Thus, SHS pregnant women may be at increased risk of developing PE and may present abnormal placental alteration and expression of AGMs and OS compared to optimal health status (OHS) pregnant women. We examined the histopathological morphology, immunohistochemical expression of AGMs antibodies and oxidative DNA damage marker in the placentae of SHS and OHS pregnant women who developed early-onset PE (EO-PE) and late-onset (LO-PE) compared to normotensive pregnancy (NTN-P).

Methods

This nested case-control study recruited 593 singleton normotensive pregnant women at baseline (10–20 weeks gestation) from the Ghanaian Suboptimal Health Status Cohort Study (GHOACS) undertaken at the Komfo Anokye Teaching Hospital, Ghana. Socio-demographic, clinical and obstetrics data were collected, and a validated SHS questionnaire-25 (SHSQ-25) was used in classifying participants into SHS (n = 297) and OHS (n = 296). Participants were followed until the time of PE diagnosis and delivery (32–42 weeks gestation). Blood samples were collected at the two-time points and were assayed for AGMs; soluble fms-like tyrosine kinase-1 (sFlt-1), placental growth factor (PIGF), vascular endothelial growth factor-A (VEGF-A), and soluble endoglin (sEng), and OS biomarkers; 8-hydroxydeoxyguanosine (8-OHdG), 8-epiprostaglandinF2-alpha (8- epi-PGF2α) and total antioxidant capacity (TAC) using ELISA. Placental samples were collected for histopathological and immunohistochemical analysis.

Results

Of the 593 pregnant women, 498 comprising 248 SHS and 250 OHS women returned for delivery and were included in the final analysis. Of the 248 SHS women, 56, 97 and 95 developed EO-PE, LO-PE and NTN-P, respectively, whereas 14, 30 and 206 of the 250 OHS mothers developed EO-PE, LO-PE and NTN-P, respectively. At baseline, SHS_NTN pregnant women had a significant imbalance in AGMs and OS biomarkers compared to OHS_NTN pregnant women (p<0.0001). At the time of PE diagnosis, SHS_NTN-P women who developed EO-PE, LO-PE, and NTN-P had lower serum levels of P1GF, VEGF-A and TAC and correspondingly higher levels of sEng, sFlt-1, 8-epiPGF2α, and 8-OHdG than OHS-NTN-P women who developed EO-PE and LO-PE, NTN-P (p<0.0001). A reduced placental size, increased foetal/placental weight ratio, and a significantly higher proportion of fibrinoid necrosis, infarction, villous fibrin, syncytial knots, calcification, chorangiosis, tunica media/vascular wall hypertrophy and chorioamnionitis was associated with the SHS group who developed PE (EO-PE>LO-PE) more than OHS groups who developed PE (EO-PE>LO-PE) when all were compared to NTN-P (p<0.0001). The intensity of antibody expression of PIGF and VEGF-A were significantly reduced, whereas Flt-1, Eng and 8-OHdG were significantly increased in placentae from SHS-pregnant women who developed EO-PE>LO-PE more than OHS- pregnant women who developed EO-PE>LO-PE when all were compared to NTN-P (p<0.0001).

Conclusion

Increased lesions, oxidative DNA damage, and imbalanced expression between pro-and anti-AGMs are associated more with SHS-embodied PE placentae rather than OHS-embodied PE subtypes, thus potentially allowing differential evaluation of PE.

Association between fetoplacental Doppler results, placental pathology, and angiogenic factors among pregnant women with anxiety

OBJECTIVE

This study aimed to evaluate whether state and trait anxiety among pregnant women were associated with fetoplacental Doppler findings, abnormal placental pathology, and placental angiogenic factors.

MATERIALS AND METHODS

A total of 102 pregnant women at 32-35 gestational weeks were recruited and examined prospectively. State and trait anxiety were measured using the State-Trait Anxiety Inventory. Using Doppler ultrasound, pulsatility index (PI) of the umbilical artery (UA), middle cerebral artery (MCA), and uterine artery (UtA) and cerebroplacental ratio (CPR) were determined. Doppler parameters were converted into multiples of the median (MoM). Abnormal placental pathology was classified into 2 groups: vascular underperfusion (VU) and histological chorioamnionitis (HCA). Immunohistochemical analysis was performed to examine placental cells staining positive for placental growth factor (PLGF) and hypoxia-inducible factor-1-α (HIF-1α), which are markers for angiogenesis and hypoxic status, respectively.

RESULTS

Women with high state anxiety scores had low MCA-PI MoM and CPR MoM, while those with high trait anxiety scores had low MCA-PI MoM. VU was associated with a higher incidence of high trait anxiety scores, and HCA was associated with a higher incidence of high state and trait anxiety scores. Regression analysis showed a relationship between maternal state anxiety on MCA-PI MoM and HCA after controlling for covariates. Maternal trait anxiety exhibited relationships with VU and HCA after adjustment.

CONCLUSION

Our results demonstrated that maternal anxiety is associated with altered fetal cerebral blood flow and abnormal placental pathology but is not associated with uteroplacental insufficiency and placental angiogenic factors.

The effects of hypothyroidism and hyperthyroidism on placental Hofbauer cells of pregnant rats

We investigated the effects of maternal thyroid disorders on Hofbauer cells of both the placenta and the fetus in pregnant rats. We divided 21 rats into three groups: control group, induced hypothyroidism (hypo) group and induced hyperthyroidism (hyper) group. Hypothyroidism was induced using propylthiouracil and hyperthyroidism was induced using L-thyroxine. We measured maternal weight, maternal free thyroxine, fetal weight, fetal viability and placental morphology. At the end of the experiment, fetuses of the hypo and hyper groups were less developed than those of the control group. In the hypo and hyper groups, the thickness of the labyrinth zone was decreased, but thickness of the basal zone and decidua basalis was increased. The number of Hofbauer cells was increased in both the hypo and hyper groups. Vascular endothelial growth factor expression was increased in both the hypo and hyper groups compared to controls. Our findings indicate that maternal thyroid disorders exert a negative effect on fetal growth and placental development.

Two patterns of cytokine production by placental macrophages

INTRODUCTION

Macrophages participate in the regulation immune and morphogenetic events in the placenta. However, these roles remain unclear for placental macrophages (Hofbauer cells). The aims of this study were to characterize the consecutive steps of cytokine production (intracellular synthesis and secretion) in placental macrophages in early and late gestation and to compare the secretory profiles of placental macrophages and villous tissue.

METHODS

Macrophages and villous tissue were isolated from placentas obtained from normal pregnancies at either 9-12 or 38-40 weeks of gestation. Intracellular cytokines were determined by flow cytometry after staining with monoclonal antibodies. Secreted cytokines were quantified by cytometric bead array and ELISA.

RESULTS

Two patterns of cytokine production were revealed in placental macrophages. Cytokines in the first group (IL-1, IL-6, IL-8, IL-10, TNFα) demonstrated low basal production and were stimulated by bacterial endotoxin. Cytokines in the second group (IL-11, IL-17A, IL-17F, TGF-β, VEGF) were characterized by constitutive production and did not respond to stimulation. Gestational age-dependent changes were observed: basal secretion of TNFα and IL-8 increased whereas IL-11 and IL-17 secretion decreased in third-trimester macrophages compared with the first-trimester cells. Comparison of cytokine production at the cellular and tissue levels suggested the contribution of the placental macrophages both in intraplacental and extraplacental cytokine production.

DISCUSSION

It would be safe to assume that the two patterns of cytokine production, revealed in our study, correspond to two regulatory roles of placental macrophages: "immune" and "morphogenetic". The inflammatory phenotype of macrophages is attenuated in early gestation and increases with the progression of pregnancy. The cytokines of the first group supposedly contribute to both local and extraplacental levels, whereas the cytokine effects of the second group are more likely confined to the placental tissue.

Placental growth factor, vascular endothelial growth factor, and hypoxia-inducible factor-1α in the placentas of women with pre-eclampsia

BACKGROUND

Although the exact mechanism of pre-eclampsia - high blood pressure and proteinuria after 20 gestational weeks - is not yet fully understood, placental growth factor (PLGF), vascular endothelial growth factor (VEGF), and hypoxia-inducible factor (HIF) are known to play important roles in vascularization and in the pathology of pre-eclampsia.

METHODS

PLGF, VEGF, and HIF-1α were evaluated by immunohistochemistry in the placentas of Sudanese women with mild or severe pre-eclampsia, and in normal controls.

RESULTS

Sixty-two women had severe pre-eclampsia, 102 had mild pre-eclampsia and 101 women served as healthy controls. Immunohistochemical staining of PLGF was significantly lower in placentas of women with severe pre-eclampsia (16%) compared with those with mild pre-eclampsia (8.8%) and placentas of normotensive women (40.6%; p < .001). Significantly more of the pre-eclamptic placentas expressed VEGF: in 32%, 17.6%, and 14.9% (p = .020) of the placentas of women with severe or mild pre-eclampsia and in controls, respectively. Significantly more of the pre-eclamptic placentas expressed HIF-1α: in 15%, 10.8%, and 5.0% of the placentas of women with severe or mild pre-eclampsia, and in controls, respectively (p = .044).

CONCLUSION

The current study showed that PLGF, VEGF, and HIF-1α are involved in the pathophysiology of pre-eclampsia.

TLR9 (Toll-Like Receptor 9) Agonist Suppresses Angiogenesis by Differentially Regulating VEGFA (Vascular Endothelial Growth Factor A) and sFLT1 (Soluble Vascular Endothelial Growth Factor Receptor 1) in Preeclampsia

Preeclampsia is a common pregnancy-specific disorder characterized by elevated blood pressure and proteinuria. Activation of the maternal immune system and impaired placental angiogenesis are thought to contribute to the pathogenesis of preeclampsia. TLR9 (Toll-like receptor 9) plays a role in innate immunity, defending the organism against infection. The purpose of this study was to determine whether TLR9 inhibits angiogenesis at the fetomaternal interface under conditions of preeclampsia. We confirmed the downregulation of VEGFA (vascular endothelial growth factor A) and upregulation of TLR9 and sFLT1 (soluble vascular endothelial growth factor receptor 1) in placentas from preeclamptic women. Then, we established a mouse model with preeclampsia-like symptoms using the synthetic TLR9 agonist CpG (cytidine-phosphate-guanosine)-ODN (oligodeoxynucleotide; ODN1826). We observed the downregulation of VEGFA and the upregulation of sFLT1 in placentas from the preeclampsia-like animal model and in trophoblasts treated with CpG-ODN (ODN2006). In addition, silencing TLR9 promoted the migration and invasion of HTR8/SVneo cells. In conclusion, TLR9 is capable of robustly suppressing angiogenesis by differentially regulating the expression of VEGFA and sFLT1 at the fetomaternal interface, potentially contributing to the development of preeclampsia.

Elucidating the Pathogenesis of Pre-eclampsia Using In Vitro Models of Spiral Uterine Artery Remodelling

PURPOSE OF REVIEW

The aim of the study is to perform a critical assessment of in vitro models of pre-eclampsia using complementary human and cell line-based studies. Molecular mechanisms involved in spiral uterine artery (SUA) remodelling and trophoblast functionality will also be discussed.

RECENT FINDINGS

A number of proteins and microRNAs have been implicated as key in SUA remodelling, which could be explored as early biomarkers or therapeutic targets for prevention of pre-eclampsia. Various 2D and 3D in vitro models involving trophoblast cells, endothelial cells, immune cells and placental tissue were discussed to elucidate the pathogenesis of pre-eclampsia. Nevertheless, pre-eclampsia is a multifactorial disease, and the mechanisms involved in its pathogenesis are complex and still largely unknown. Further studies are required to provide better understanding of the key processes leading to inappropriate placental development which is the root cause of pre-eclampsia. This new knowledge could identify novel biomarkers and treatment strategies.

sFlt-1/PlGF for prediction of early-onset pre-eclampsia: STEPS (Study of Early Pre-eclampsia in Spain)

OBJECTIVE

A high ratio of soluble fms-like tyrosine kinase-1 (sFlt-1) to placental growth factor (PlGF) has been linked to pre-eclampsia (PE). We evaluated the sFlt-1/PlGF ratio as a predictive marker for early-onset PE in women at risk of PE.

METHODS

This prospective, Spanish, multicenter study included pregnant women with a risk factor for PE, including intrauterine growth restriction, PE, eclampsia or hemolysis, elevated liver enzymes and low platelet count syndrome in previous pregnancy, pregestational diabetes or abnormal uterine artery Doppler. The primary objective was to show that the sFlt-1/PlGF ratio at 20, 24 and 28 weeks' gestation was predictive of early-onset PE (< 34 + 0 weeks). Serum sFlt-1 and PlGF were measured at 20, 24 and 28 weeks. Multivariate logistic regression was used to develop a predictive model.

RESULTS

A total of 819 women were enrolled, of which 729 were suitable for analysis. Of these, 78 (10.7%) women developed PE (24 early onset and 54 late onset). Median sFlt-1/PlGF ratio at 20, 24 and 28 weeks was 6.3 (interquartile range (IQR), 4.1-9.3), 4.0 (IQR, 2.6-6.3) and 3.3 (IQR, 2.0-5.9), respectively, for women who did not develop PE (controls); 14.5 (IQR, 5.5-43.7), 18.4 (IQR, 8.2-57.9) and 51.9 (IQR, 11.5-145.6) for women with early-onset PE; and 6.7 (IQR, 4.6-9.9), 4.7 (IQR, 2.8-7.2) and 6.0 (IQR, 3.8-10.5) for women with late-onset PE. Compared with early-onset PE, the sFlt-1/PlGF ratio was significantly lower in controls (P < 0.001 at each timepoint) and in women with chronic hypertension (P < 0.001 at each timepoint), gestational hypertension (P < 0.001 at each timepoint) and late-onset PE (P < 0.001 at each timepoint). A prediction model for early-onset PE was developed, which included the sFlt-1/PlGF ratio plus mean arterial pressure, being parous and previous PE, with areas under the receiver-operating characteristics curves of 0.86 (95% CI, 0.77-0.95), 0.91 (95% CI, 0.85-0.97) and 0.93 (95% CI, 0.86-0.99) at 20, 24 and 28 weeks, respectively, and was superior to models using the sFlt-1/PlGF ratio alone or uterine artery mean pulsatility index.

CONCLUSIONS

The sFlt-1/PlGF ratio can improve prediction of early-onset PE for women at risk of this condition. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Maternal testosterone and placental function: Effect of electroacupuncture on placental expression of angiogenic markers and fetal growth

Women with polycystic ovary syndrome (PCOS) have elevated circulating androgens during pregnancy and are at an increased risk of adverse pregnancy outcomes. Here we tested the hypotheses that maternal androgen excess decrease placental and fetal growth, and placental expression of markers of steroidogenesis, angiogenesis and sympathetic activity, and that acupuncture with low-frequency electrical stimulation prevents these changes. Pregnant rats were exposed to vehicle or testosterone on gestational day (GD)15-19. Low-frequency electroacupuncture (EA) or handling, as a control for the EA procedure, was given to control or testosterone exposed dams on GD16-20. On GD21, blood pressure was measured and maternal blood, fetuses and placentas collected. Placental steroid receptor expression and proteins involved in angiogenic, neurotrophic and adrenergic signaling were analyzed. EA did not affect any variables in control rats except maternal serum corticosterone, which was reduced. EA in testosterone exposed dams compared with controls increased systolic pressure by 30%, decreased circulating norepinephrine and corticosterone, fetal and placental weight and placental VEGFR1 and proNGF protein expression, and increased the VEGFA/VEGFR1 ratio, mature NGF (mNGF) and the mNGF/proNGF ratio. In conclusion, low-frequency EA in control animals did not have any negative influence on any of the studied variables. In contrast, EA in pregnant dams exposed to testosterone increased blood pressure and impaired placental growth and function, leading to decreased fetal growth.

Systematic Review of Micro-RNA Expression in Pre-Eclampsia Identifies a Number of Common Pathways Associated with the Disease

Background

Pre-eclampsia (PE) is a complex, multi-systemic condition of pregnancy which greatly impacts maternal and perinatal morbidity and mortality. MicroRNAs (miRs) are differentially expressed in PE and may be important in helping to understand the condition and its pathogenesis.

Methods

Case-control studies investigating expression of miRs in PE were collected through a systematic literature search. Data was extracted and compared from 58 studies to identify the most promising miRs associated with PE pathogenesis and identify areas of methodology which could account for often conflicting results.

Results

Some of the most frequently differentially expressed miRs in PE include miR-210, miR-223 and miR-126/126* which associate strongly with the etiological domains of hypoxia, immunology and angiogenesis. Members of the miR-515 family belonging to the imprinted chromosome 19 miR cluster with putative roles in trophoblast invasion were also found to be differentially expressed. Certain miRs appear to associate with more severe forms of PE such as miR-210 and the immune-related miR-181a and miR-15 families. Patterns of miR expression may help pinpoint key pathways (e.g. IL-6/miR-223/STAT3) and aid in untangling the heterogeneous nature of PE. The detectable presence of many PE-associated miRs in antenatal circulatory samples suggests their usefulness as predictive biomarkers. Further progress in ascertaining the clinical value of miRs and in understanding how they might contribute to pathogenesis is predicated upon resolving current methodological challenges in studies. These include differences in diagnostic criteria, cohort characteristics, sampling technique, RNA isolation and platform-dependent variation in miR profiling.

Conclusion

Reviewing studies of PE-associated miRs has revealed their potential as informants of underlying target genes and pathways relating to PE pathogenesis. However, the incongruity in results across current studies hampers their capacity to be useful biomarkers of the condition.

Identification of novel biomarkers for preeclampsia on the basis of differential expression network analysis

Preeclampsia (PE) is a severe pregnancy complication, which is a leading cause of maternal and fetal mortality. The present study aimed to screen potential biomarkers for the diagnosis and prediction of PE and to investigate the underlying mechanisms of PE development based on the differential expression network (DEN). The microarray datasets E-GEOD-6573 and E-GEOD-48424 were downloaded from the European Bioinformatics Institute database. Differentially expressed genes (DEGs) between the PE and normal groups were screened by Significant Analysis of Microarrays with the cutoff value of a |log2 fold change| of >2, and a false discovery rate of <0.05. The DEN was constructed based on the differential and non-differential interactions observed. In addition, genes with higher connectivity degrees in the DEN were identified on the basis of centrality analysis, while disease genes were also extracted from the DEN. In order to understand the functional roles of genes in DEN, Gene Ontology (GO) and pathway enrichment analyses were performed. The present results indicated that a total of 225 genes were considered as DEGs in the PE group, while 466 nodes and 314 gene interactions were involved in the DEN. Among these 466 nodes, 4 nodes with higher degrees were identified, including ubiquitin C (UBC), small ubiquitin-like modifier 1 (SUMO1), SUMO2 and RAD21 homolog (S. pombe) (RAD21). Notably, UBC was also found to be a disease gene. UBC, RAD21, SUMO2 and SUMO1 were markedly enriched in the regulation of programmed cell death, as well as in the regulation of apoptosis, cell cycle and chromosomal part. In conclusion, based on these results, we suggest that UBC, RAD21, SUMO2 and SUMO1 may be reliable biomarkers for the prediction of the development and progression of PE.

Association between Placental Lesions, Cytokines and Angiogenic Factors in Pregnant Women with Preeclampsia

Preeclampsia (PE) is considered the leading cause of maternal and perinatal morbidity and mortality. The placenta seems to play an essential role in this disease, probably due to factors involved in its formation and development. The present study aimed to investigate the association between placental lesions, cytokines and angiogenic factors in pregnant women with preeclampsia (PE). We evaluated 20 normotensive pregnant women, 40 with early-onset PE and 80 with late-onset PE. Placental samples were analyzed for histopathology, immunohistochemistry and determination of granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-10 (IL-10), transforming growth factor-beta 1 (TGF-β₁), tumor necrosis factor-alpha (TNF-α), placental growth factor (PlGF), vascular endothelial growth factor (VEGF), fms-like tyrosine-kinase-1 (Flt-1) and endoglin (Eng) levels. Higher percentages of increased syncytial knots and increased perivillous fibrin deposits, and greater levels of TNF-α, TGF-β1and Flt-1 were detected in placentas from early-onset PE. Levels of IL-10, VEGF and PlGF were decreased in PE versus normotensive placentas. Both the TNF-α/IL-10 and sFlt-1/PlGF ratios were higher in placental homogenate of early-onset PE than late-onset PE and control groups. The more severe lesions and the imbalance between TNF-α/IL-10 and PlGF/sFlt-1 in placentas from early-onset PE allows differentiation of early and late-onset PE and suggests higher placental impairment in early-onset PE.

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.

HIF-1 Alpha and Placental Growth Factor in Pregnancies Complicated With Preeclampsia: A Qualitative and Quantitative Analysis

BACKGROUND

The pathophysiology of preeclampsia is not clearly understood worldwide. Hypoxia inducible factor 1α (HIF-1α) is thought to be the preliminary factor for the hypoxic conditions prevailing in preeclampsia, which causes imbalance in the expression of angiogenic proteins. A proangiogenic protein, placental growth factor (PIGF), is reported to be dysregulated in preeclampsia. Therefore, this study focuses on the investigation of HIF-1α and PIGF in preeclamptic conditions and a possible molecular association between them.

METHODS

Placental tissue (n = 45 + 45) and serum samples (n = 80 + 80) of preeclamptic patients and healthy control were collected and processed for the analysis of HIF-1α and PIGF by immunohistochemistry and enzyme-linked immunosorbent assay (ELISA).

RESULTS

In preeclamptic group, the significant nuclear and cytoplasmic expression of HIF-1α was noticed in syncytiotrophoblast (P = 0.0001) but in control placenta, it was localized to cytoplasm (P = 0.0001). The intensity of PIGF expression was lower in syncytiotrophoblast cytoplasm (P = 0.0001) in preeclamptic cases as compared with control. Also, the significant upregulated concentration of HIF-1α and downregulated PIGF was observed in serum samples of preeclamptic woman (P = 0.0001). Thus, there was a significant direct negative correlation between HIF-1α and PIGF both at tissue and serum level (P < 0.01).

CONCLUSION

The direct inverse association between HIF-1α and PIGF in serum and placental tissues may be responsible for the low oxidative stress and endothelial dysfunction, leading to the pathogenesis of preeclampsia.

Differential placental methylation and expression of VEGF, FLT-1 and KDR genes in human term and preterm preeclampsia

Background

Preeclampsia, a pregnancy complication of placental origin is associated with altered expression of angiogenic factors and their receptors. Recently, there is considerable interest in understanding the role of adverse intrauterine conditions in placental dysfunction and adverse pregnancy outcomes. Since we have observed changes in placental global DNA methylation levels in preeclampsia, this study was undertaken to examine gene promoter CpG methylation and expression of several angiogenic genes.

We recruited 139 women comprising, 46 normotensive women with term delivery (≥37 weeks), 45 women with preeclampsia delivering preterm (<37 weeks) and 48 women with preeclampsia delivering at term. Expression levels and promoter CpG methylation of VEGF, FLT-1 and KDR genes in placentae from respective groups were determined by Taqman-based quantitative real time PCR and by the Sequenom® EpiTYPER™ technology respectively.

Results

We observed several differentially methylated CpG sites in the promoter regions of VEGF, FLT-1 and KDR between the normotensive and preeclampsia groups. We specifically observed hypomethylated CpGs in the promoter region and an increased expression of VEGF gene between term and preterm preeclampsia. However, mean promoter CpG methylation could not account for the higher expression of FLT-1 and KDR in preterm preeclampsia as compared to normotensive group.

Conclusions

Our data indicates altered DNA methylation patterns in the VEGF, FLT-1 and KDR genes in preeclampsia as compared to the normotensive group, which could be involved in the pathophysiology of preeclampsia. Hypomethylation of VEGF promoter and consequent upregulation of VEGF mRNA levels could be a compensatory mechanism to restore normal angiogenesis and blood flow in preterm preeclampsia. This study suggests a role of altered DNA methylation in placental angiogenesis and in determining adverse pregnancy outcomes.

The promise of angiogenic markers for the early diagnosis and prediction of preeclampsia

BACKGROUND

An imbalance in circulating factors that regulate blood vessel formation and health, referred to as angiogenic factors, plays a central role in the pathogenesis of preeclampsia.

CONTENT

Several studies have demonstrated a strong association between altered circulating angiogenic factors and preeclampsia. These factors include circulating antiangiogenic proteins such as soluble fms-like tyrosine kinase 1 and soluble endoglin and proangiogenic protein such as placental growth factor. Abnormalities in these circulating angiogenic factors are not only present during clinical disease, but also antedate clinical signs and symptoms by several weeks. These alterations are particularly prominent in patients who present with preeclamptic signs and symptoms prematurely and/or in patients with severe preeclampsia. The availability of automated platforms for the rapid measurement of circulating angiogenic proteins in blood samples has now allowed researchers and clinicians to evaluate the utility of these assays in the diagnosis of the disease, in the stratification of patients in clinical trials, or in the monitoring of therapies. In this review we highlight the various studies that have been performed, with a focus on large validation studies.

SUMMARY

Measurement of circulating angiogenic proteins for the diagnosis and prediction of preeclampsia is still at an early stage but is rapidly evolving. Standardization across the various automated platforms and prospective studies that demonstrate clinical utility are needed.

VEGF and its soluble receptor VEGFR-2 in hypertensive disorders during pregnancy: the Indian scenario

Hypertensive disorders are the most common medical problem encountered during pregnancy due to defective angiogenesis during placental development. Vascular endothelial growth factor (VEGF) is one of the angiogenic growth factors that stimulates angiogenesis. The recombinant form of its soluble receptor VEGF receptor-2 (sVEGFR-2) has anti-angiogenic activity. However, there is a paucity of information on serum VEGF and sVEGFR-2 concentrations in different sub-groups of hypertensive disorders during pregnancy. In this cross-sectional study, we evaluated the concentrations and the diagnostic utility of VEGF and sVEGFR-2 in gestational hypertension (GH, n=90), pre-eclampsia (PE, n=180), eclampsia (n=90) and control (n=180) pregnancy at different gestations. VEGF levels were significantly higher in PE and eclamptic (median=19.53 pg ml(-1); 60.36 pg ml(-1), P=0.0001) groups as compared with the control ones (median=18 pg ml(-1)). But, the serum sVEGFR-2 levels were found to be significantly decreased from GH to eclampsia groups (median=5196; 3972 pg ml(-1)) as compared with control groups (median=7417 pg ml(-1)). As the gestation advanced, there was an inverse association in the serum concentrations of sVEGFR-2 among the control, GH, PE and eclampsia groups. At both 34 and >34 weeks of gestations, higher sensitivity and specificity were observed for sVEGFR-2 in differentiating GH (50.8, 50%; 76.6, 76.6%), PE (63, 63%; 90, 90%) and eclampsia (65, 66.6%; 90, 90%) from the control pregnancy. This upregulation of VEGF and downregulation of sVEGFR-2 concentrations in different study groups may be due to hypoxia and could be involved intimately in the pathogenesis of these disorders. This study may contribute in understanding etio-pathogenesis of different hypertensive disorders during pregnancy.

Implication of umbilical cord in preeclampsia

OBJECTIVES

To investigate the role of biochemical changes in the umbilical cord and placenta in developing preeclampsia (PE).

SUBJECTS AND METHODS

Thirty women with PE and 15 healthy pregnant women as controls were enrolled in this study. Vascular endothelial growth factor (VEGF), soluble vascular endothelial growth factor receptor 1 (sVEGFR-1), platelet-derived endothelial cell growth factor (PD-ECGF), neutrophil elastase and nitric oxide (NO) were measured.

RESULTS

Both serum (maternal and fetal) and tissue (placenta and umbilical cord) levels of VEGF, sVEGFR-1, PD-ECGF and neutrophil elastase were significantly increased, whereas NO was significantly decreased (except placental tissue showed no changes) in preeclamptic patients. The cord serum level of PD-ECGF was significantly higher in severe PE compared to mild PE and normal pregnant women. The placental and cord tissue levels of PD-ECGF and neutrophil elastase were significantly higher in severe PE, while the cord tissue level of NO was significantly lower in severe PE.

CONCLUSION

Our data showed that umbilical cord vessels and stroma can serve as an additional source of vasoactive and angiogenic substances that contribute to the biochemical changes occurring in PE.

Soluble and membranous vascular endothelial growth factor receptor-2 in pregnancies complicated by pre-eclampsia

PURPOSE

There is a paucity of information on the serum soluble vascular endothelial growth factor receptor-2 (sVEGFR-2) concentrations, membranous VEGFR-2 expression and the mechanism involved in their modulations during the clinical onset of pre-eclampsia. This cross-sectional study was conducted to evaluate the concentration of sVEGFR-2 in serum and to investigate the expression of membranous VEGFR-2 in placentae of pre-eclampsia group.

MATERIALS AND METHODS

The serum levels of sVEGFR-2 (n = 120) and the expression of membranous VEGFR-2 in placentae (n = 100) were analysed at third trimester of pregnancy by enzyme linked immunosorbent assay (ELISA) and immunohistochemistry respectively. The diagnostic parameters of sensitivity, specificity and association of soluble and membranous VEGFR-2 in these patients were evaluated.

RESULTS

The serum levels of sVEGFR-2 in pre-eclampsia patients were found to be significantly reduced (p = 0.01, p = 0.001) in early and late pre-eclamptic sub-groups as compared to their respective third trimester control sub-groups. Also, the receiver operating characteristic (ROC) curve analysis showed a cut-off value of 7350.4 pg/mL, higher sensitivity (76%) and specificity (76%) for sVEGFR-2 in late onset (> 34 weeks) pre-eclamptic group. Significant down-regulation of membranous VEGFR-2 immunoreactivity was observed in all the placental cells (p = 0.0001) at > 34 weeks preeclamptic group.

CONCLUSION

The reduced serum levels of soluble VEGFR-2 and the down-regulated expression of membranous VEGFR-2 in the study group denoted abnormality in VEGF mediated placental function in all placental cells and thus VEGFR-2 may be a key factor, intimately associated with pre-eclampsia. This study shows the clinical utility of soluble and membranous VEGFR-2 in pre-eclampsia patients.

Long-term maternal and subsequent pregnancy outcomes 5 years after hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome

OBJECTIVE

To evaluate subsequent pregnancy outcome and impact of gestational age at onset of HELLP on long-term prognosis after HELLP over an average follow-up of 5 years

STUDY DESIGN

One hundred twenty-eight patients with a history of HELLP filled out questionnaires and sent their medical records. Hemolysis, elevated liver enzymes, and low platelets data were stratified according to gestational age at onset of HELLP < or =28 weeks and >28 weeks.

RESULTS

Fifty-three patients had subsequent pregnancies with 24% complicated by HELLP and 28% by preeclampsia. During follow-up, 33% of the patients had new onset hypertension develop, 32% had depression develop, 26% had anxiety develop, and 2.4% required dialysis. There was no significant difference in long-term outcome between comparison groups.

CONCLUSION

Patients with a history of HELLP are at increased risk for preeclampsia and HELLP as well as long-term morbidities as depression and chronic hypertension. Gestational age at the onset of HELLP could be a predictor for long-term outcome.