Suppression of serum vascular endothelial growth factor immunoreactivity in normal pregnancy and in pre-eclampsia

CircRNA_06354 might promote early-onset preeclampsia in humans via hsa-miR-92a-3p/vascular endothelial growth factor-A

BACKGROUND

Early-onset preeclampsia (EOPE) is a serious pregnancy disorder with multisystem complications. Recently, circRNA was reported to participate in the progression of EOPE. However, the role and mechanism of circRNA_06354 in the pathophysiological development of EOPE remain unclear.

METHODS

Blood samples from patients with EOPE and healthy pregnant controls (CTRL) were analyzed by RNA-seq. functions and mechanisms of circRNA_06354 in EOPE were investigated by a series of experiments. An EOPE rat model was constructed to detect the expression levels of circRNA_06354.

RESULTS

The level of circRNA_06354 was altered in EOPE and CTRL individuals, as well as EOPE and CTRL rats. CircRNA_06354 had a sensitivity of 88.9% and a specificity of 100% in predicting EOPE. Subcellular localization indicated that circRNA_06354 was primarily detected in the cytoplasm of HTR8-/SV-neo cells and the cytotrophoblast of EOPE placentas. In addition, circRNA_06354 transcription was markedly higher than that of its linear counterpart. RNA pull-down assays implied that hsa-miR-92a-3p might sponge circRNA_06354. Vascular endothelial growth factor-A (VEGF-A) levels were found to be increased in EOPE patients. Moreover, overexpression of circRNA_06354 suppressed the migration, invasion and tube formation of trophoblastic cells invading spiral arteries or the endometrium.

CONCLUSION

CircRNA_06354 inhibits trophoblastic cell invasion, migration and tube formation toward the endometrium in the initiation of EOPE. The circRNA_06354/hsa-miR-92a-3p/VEGF-A axis might be a therapeutic target in the prevention and treatment of EOPE.

FtMt reduces oxidative stress-induced trophoblast cell dysfunction via the HIF-1α/VEGF signaling pathway

BACKGROUND

Preeclampsia (PE) is a complication of pregnancy that causes long-term adverse outcomes for the mother and fetus and may even lead to death. Oxidative stress caused by the imbalance of oxidants and antioxidants in the placenta has been considered as one of the key mechanisms of preeclampsia (together with inflammation, etc.), in which the placental mitochondria play an important role. The expression of hypoxia-inducible factor-1 (HIF-1α) and vascular endothelial growth factor (VEGF) is known to be increased in patients with PE. Mitochondrial ferritin (FtMt) is known to protect the mitochondria from oxidative stress, although its specific role in PE remains unclear.

METHODS

We used qRT-PCR and western blotting to detect the expression levels of FtMt, HIF-1α, and VEGF in placental tissues from patients with PE. Human chorionic trophoblast cells were also administered with hypoxia treatment, followed by the detection of cell proliferation, invasion and angiogenic capacity by CCK8, Transwell, and endothelial cell angiogenesis assays; we also detected the expression of HIF-1α and VEGF in these cells. Finally, overexpression or inhibitory FtMt lentiviral vectors, along with negative control vectors, were constructed and transfected into hypoxia-treated human chorionic trophoblast cells; this was followed by analyses of cell function.

RESULTS

The expression levels of FtMt, HIF-1α and VEGF in the PE group were higher than those in the control group (P < 0.05). Following hypoxia, there was an increase in the expression levels of HIF-1α and VEGF protein in trophoblast cells. There was also an increase in invasion ability and vascular formation ability along with a reduction in cell proliferation ability. These effects were reversed by transfecting cells with the knockout FtMt lentivirus vector. The differences were statistically significant.

CONCLUSION

Analyses showed that FtMt plays a key role in the vascular regulation of PE trophoblast cells after hypoxia possibly acting via the HIF-1α/VEGF signaling pathway. These results provide us an enhanced understanding of the pathogenesis of PE and suggest that the HIF-1α/VEGF signaling pathway represents a new target for the treatment of PE.

Paeoniflorin alleviates NG-nitro-L-arginine methyl ester (L-NAME)-induced gestational hypertension and upregulates silent information regulator 2 related enzyme 1 (SIRT1) to reduce H2O2-induced endothelial cell damage

Pregnancy-induced hypertension (PIH) is a leading cause of maternal mortality. Paeoniflorin has been reported to alleviate hypertension, thus relieving the injury of target organ. This study aimed to investigate the role of paeoniflorin in PIH development by regulating SIRT1 in rats. The mean arterial pressure (MAP), urine protein and histopathological damage of placenta in gestational hypertension rats were, respectively, detected by noninvasive tail-artery pressure measuring instrument, BCA method and H&E staining. The viability of human umbilical vein endothelial cells (HUVECs) treated with paeoniflorin or/and H₂O₂ was observed by CCK-8 assay. SIRT1 protein expression in HUVECs treated with paeoniflorin or/and H₂O₂ was analyzed by Western blot. Tunel assay, wound healing assay and tube formation assay were used to detect the apoptosis, migration and tube formation of HUVECs administrated with paeoniflorin or/and H₂O₂ or/and EX527 (SIRT1 inhibitor). As a result, MAP, urine protein and histopathological damage of placenta were enhanced in PIH rats, which were then alleviated by paeoniflorin. Paeoniflorin decreased the levels of sFlt-1, PlGF and VEGF in serum and placental tissues of gestational hypertension rats as well as the inflammatory response and oxidative stress. In addition, paeoniflorin promoted the expressions of SIRT1 and NO/eNOS and inhibited the production of iNOS in gestational hypertension rats to improve vascular endothelial cell injury. However, SIRT1 inhibition could suppress the protective effects of paeoniflorin on endothelial dysfunction of H₂O₂-induced HUVECs. In conclusion, paeoniflorin could improve gestational hypertension development by upregulating SIRT1.

Regulation of Uterine Spiral Artery Remodeling: a Review

Extravillous trophoblast remodeling of the uterine spiral arteries is essential for promoting blood flow to the placenta and fetal development, but little is known about the regulation of this process. A defect in spiral artery remodeling underpins adverse conditions of human pregnancy, notably early-onset preeclampsia and fetal growth restriction, which result in maternal and fetal morbidity and mortality. Many in vitro studies have been conducted to determine the ability of growth and other factors to stimulate trophoblast cells to migrate across a synthetic membrane. Clinical studies have investigated whether the maternal levels of various factors are altered during abnormal human pregnancy. Animal models have been established to assess the ability of various factors to recapitulate the pathophysiological symptoms of preeclampsia. This review analyzes the results of the in vitro, clinical, and animal studies and describes a nonhuman primate experimental paradigm of defective uterine artery remodeling to study the regulation of vessel remodeling.

Vascular endothelial growth factor C/A 2578 gene polymorphism and umbilical artery Doppler in preeclamptic women

INTRODUCTION

Preeclampsia is strongly associated with placental hypoperfusion. Genetic factors have an impact on the pathogenesis of preeclampsia. The aim is to assess the association of Vascular Endothelial Growth Factor (C2578A) gene polymorphism with the occurrence and severity of preeclampsia and the umbilical artery Doppler changes among preeclamptic women.

MATERIALS AND METHODS

This case-control study was conducted in clinical and Chemical pathology and Obstetrics departments in Beni- Suef University, Egypt. Two hundred and ninety pregnant women above 20 weeks gestational age until delivery were divided into 2 main groups. The patient group included 145 preeclamptic women who were further sub grouped according to the severity of preeclampsia into 82 severe and 63 mild cases. Control group included 145 normotensive pregnant women. Our primary outcome was detection of VEGF C 2578 A gene mutations by a polymerase chain reaction. A secondary outcome was Doppler changes in the pulsatility index of the umbilical artery compared with VEGF genotypes.

RESULTS

Our study showed that VEGF C 2578 A genotype and alleles frequencies were not related to the occurrence of preeclampsia (p-value 0.513 and 0.549, respectively), odds ratio (95%CI) 1.154 (0.724-1.848). Mild preeclamptic cases showed no significance comparing VEGF genotypes studied and pulsatility index of the umbilical artery. However, severe cases showed p-value < 0.0001.

CONCLUSION

We concluded that VEGF 2578C/A polymorphism had no association with the occurrence of preeclampsia in studied groups, whereas there was a significant relationship among severe cases between CA and CC genotypes and pulsatility index of the umbilical artery.

Association between Vascular Endothelial Growth Factor Gene Polymorphisms and Pre-Eclampsia Susceptibility: An Updated Meta-Analysis

Objectives: The aim of this study was to assess the genetic association between vascular endothelial growth factor (VEGF) gene polymorphisms and the risk of pre-eclampsia (PE).Methods: A systematic literature search of several databases (PubMed, Embase, and the China National Knowledge Infrastructure (CNKI)) was conducted for case-control trials comparing VEGF polymorphisms (+936C/T, -634G/C, -2578C/A, and -1154G/A) with the risk of PE. Meta-analysis was performed using the Stata 12.0 software.Results: Twenty-three case-control studies on a total of 2597 PE patients and 3075 controls were included in our meta-analysis. The +936C/T polymorphism was observed to be associated with the risk of PE in the overall population (T vs. C: odds ratios (OR) = 1.434, 95% confidence interval (CI) = 1.120-1.836, P = .004). However, the -634G/C, -2578C/A, and -1154G/A polymorphisms showed no association with the risk of PE. A subgroup analysis based on ethnicity found that the +936C/T polymorphism was associated with the risk of PE in both Europeans and Asians. Furthermore, the -634G/C polymorphism was found to be associated with the risk of PE in Europeans (C vs. G: OR = 1.428, 95% CI = 1.141-1.778, P = .002). The polymorphisms at other loci were not associated with the risk of PE.Conclusion: This meta-analysis suggests that VEGF +936C/T polymorphism, rather than -634G/C, -2578C/A, or -1154G/A polymorphisms, is associated with the risk of PE in the overall study population. However, the -634G/C polymorphism may be associated with the risk of developing PE in Europeans.

Friends Turned Foes: Angiogenic Growth Factors beyond Angiogenesis

Angiogenesis, the formation of new blood vessels from pre-existing ones is a biological process that ensures an adequate blood flow is maintained to provide the cells with a sufficient supply of nutrients and oxygen within the body. Numerous soluble growth factors and inhibitors, cytokines, proteases as well as extracellular matrix proteins and adhesion molecules stringently regulate the multi-factorial process of angiogenesis. The properties and interactions of key angiogenic molecules such as vascular endothelial growth factors (VEGFs), fibroblast growth factors (FGFs) and angiopoietins have been investigated in great detail with respect to their molecular impact on angiogenesis. Since the discovery of angiogenic growth factors, much research has been focused on their biological actions and their potential use as therapeutic targets for angiogenic or anti-angiogenic strategies in a context-dependent manner depending on the pathologies. It is generally accepted that these factors play an indispensable role in angiogenesis. However, it is becoming increasingly evident that this is not their only role and it is likely that the angiogenic factors have important functions in a wider range of biological and pathological processes. The additional roles played by these molecules in numerous pathologies and biological processes beyond angiogenesis are discussed in this review.

Human placental growth hormone in normal and abnormal fetal growth

Human placental growth hormone (PGH), encoded by the growth hormone (GH) variant gene on chromosome 17, is expressed in the syncytiotrophoblast and extravillous cytotrophoblast layers of the human placenta. Its maternal serum levels increase throughout pregnancy, and gradually replaces the pulsatile secreted pituitary GH. PGH is also detectable in cord blood and in the amniotic fluid. This placental-origin hormone stimulates glyconeogenesis, lipolysis and anabolism in maternal organs, and influences fetal growth, placental development and maternal adaptation to pregnancy. The majority of these actions are performed indirectly by regulating maternal insulin-like growth factor-I levels, while the extravillous trophoblast involvement indicates a direct effect on placental development, as it stimulates trophoblast invasiveness and function via a potential combination of autocrine and paracrine mechanisms. The current review focuses on the role of PGH in fetal growth. In addition, the association of PGH alterations in maternal circulation and placental expression in pregnancy complications associated with abnormal fetal growth is briefly reviewed.

Effect of vascular endothelial growth factors A, C, and D in HIV-associated pre-eclampsia

OBJECTIVE

To measure and correlate the level of vascular endothelial growth factors A, C, and D in HIV-associated pre-eclampsia.

METHODS

VEGF-A, VEGF-C, and VEGF-D were measured in serum of 76 normotensive and pre-eclamptic pregnant women stratified by HIV status using Bio-Plex.

RESULTS

No significant difference was shown between pre-eclamptic and normotensive and between HIV negative and positive women. A strong significant positive correlation was demonstrated between VEGF-A and VEGF-C, VEGF-A and VEGF-D, and VEGF-C and VEGF D (p < 0.0001).

CONCLUSION

This study demonstrates a significant correlation between VEGF-A, VEGF-C, and VEGF-D and no difference in pre-eclamptic and normotensive pregnant women stratified by HIV status suggesting some neutralization of the immune response in HIV-associated pre-eclampsia.

Assessment of Serum Vascular Endothelial Growth Factor Levels in Pregnancy-Induced Hypertension Patients

Objective. The objective of the study was to assess the serum vascular endothelial growth factor (VEGF) levels in peripheral blood of patients with pregnancy-induced hypertension (PIH) and find association between serum VEGF levels and PIH. Methods. Thirty-five PIH subjects, 35 normal pregnant females, and 20 normal healthy females were included in the study. Detailed history, clinical examination, and relevant biochemical parameters were assessed; serum VEGF levels were estimated using Double-antibody enzyme-linked immunosorbent assay. Results. The study groups were found to be age matched (p = 0.38). VEGF level in the pregnancy-induced hypertensive group (median = 109.19 (3.38 ± 619)) was significantly higher than the normal pregnant (median = 20.82 (1.7-619)) and control (median = 4.92 (1.13-13.07)) group and the difference between these three groups was significant (p < 0.0001). The 3 groups are found to be significantly different in terms of RBS (p = 0.01), urea (p < 0.0001), creatinine (p = 0.0005), AST (p = 0.0032), ALT (p = 0.0007), total protein (p = 0.0004), albumin (p < 0.0001), calcium (p = 0.001), and sodium (p = 0.02), while no statistically significant difference was found between total bilirubin (p = 0.167), direct bilirubin (p = 0.07), uric acid (p = 0.16), and potassium (p = 0.14). Conclusion. Significantly higher levels of serum VEGF were noted in PIH subjects compared to normal pregnant and control subjects.

Vascular Endothelial Growth Factor-A (VEGF-A) Mediates Activin A-Induced Human Trophoblast Endothelial-Like Tube Formation

Remodeling of maternal spiral arteries during pregnancy requires a subpopulation of extravillous cytotrophoblasts (EVTs) to differentiate into endovascular EVTs. Activin A, which is abundantly expressed at the maternal-fetal interface, has been shown to promote trophoblast invasion, but its role in endovascular differentiation remains unknown. Vascular endothelial growth factor-A (VEGF-A) is well recognized as a key regulator in trophoblast endovascular differentiation. Whether and how activin A might regulate VEGF-A production in human trophoblasts and its relationship to endovascular differentiation have yet to be determined. In the present study, we found that activin A increased VEGF-A production in primary and immortalized (HTR8/SVneo) human EVT cells. In addition, activin A enhanced HTR8/SVneo endothelial-like tube formation, and these effects were attenuated by pretreatment with small interfering RNA targeting VEGF-A or the VEGF receptor 1/2 inhibitor SU4312. Pretreatment with the activin/TGF-β type 1 receptor (ALK4/5/7) inhibitor SB431542 abolished the stimulatory effects of activin A on phosphorylated mothers against decapentaplegic (SMAD)-2/3 phosphorylation, VEGF-A production, and endothelial-like tube formation. Moreover, small interfering RNA-mediated down-regulation of SMAD2, SMAD3, or common SMAD4 abolished the effects of activin A on VEGF-A production and endothelial-like tube formation. In conclusion, activin A may promote human trophoblast cell endothelial-like tube formation by up-regulating VEGF-A production in an SMAD2/3-SMAD4-dependent manner. These findings provide insight into the cellular and molecular events regulated by activin A during human implantation.

Vascular endothelial growth factor (VEGF)-634G/C polymorphism was associated with severe pre-eclampsia and lower serum VEGF level

AIM

Vascular endothelial growth factor (VEGF) is an angiogenic factor whose production is increased in pre-eclampsia (PE). Therefore, the present study was conducted aiming at assessing the possible association of VEGF polymorphisms with PE susceptibility in the southeast of Iran.

MATERIAL AND METHODS

Overall, 192 PE women and 186 unrelated age-matched normotensive pregnant women were genotyped for the VEGF-2578C/A (rs699947), -1154G/A (rs1570360), and -634G/C (rs2010963) polymorphisms using the polymerase chain reaction-restriction fragment length polymorphism method. Serum VEGF levels were determined by the enzyme-linked immunosorbent assay method.

RESULTS

There was no significant difference in VEGF-2578C/A, -1154G/A and -634G/C polymorphisms between PE women and controls. However, the frequency of VEGF-634GC and CC genotypes was significantly higher in women with severe PE compared to mild PE and controls. In addition, serum VEGF levels were significantly lower in PE women. The VEGF-634CC genotype was associated with lower serum VEGF levels compared to the VEGF-634GG genotype. Moreover, serum VEGF levels were significantly lower in individuals with the VEGF-634CC genotype compared to VEGF-634GC genotype only in the control group. The mean serum VEGF levels did not differ significantly between genotypes of VEGF-2587C/A and -1154G/A polymorphisms.

CONCLUSION

Our findings suggest that the association of VEGF-634G/C polymorphisms with severe PE and the VEGF-634CC genotype was correlated with lower serum VEGF levels.

Vascular endothelial growth factor and endothelin-1 levels in normal pregnant women and pregnant women with pre-eclampsia

The aim of the study was to estimate the levels of vascular endothelial growth factor (VEGF) and endothelin-1 (ET-1) in maternal serum from normal pregnant women and women with pre-eclampsia. Serum concentrations of VEGF and ET-1 were measured in maternal blood in control group (n = 40) and in pregnancies complicated by pre-eclampsia (n = 40). Results showed that maternal VEGF levels were significantly raised in women with pre-eclampsia (p < 0.001). ET-1 concentration was not significantly different among women with pre-eclampsia compared with that in the control group. It was concluded that an increase in serum VEGF level was demonstrated in pre-eclampsia, suggesting that VEGF is involved in pathogenesis of pre-eclampsia. Further studies are needed to determine the serum concentrations of VEGF in pregnant women before the development of pre-eclampsia.

Cord blood biomarkers of vascular endothelial growth (VEGF and sFlt-1) and postnatal growth: a preterm birth cohort study

BACKGROUND

Preterm infants are at risk for postnatal growth failure (PGF). Identification of biomarkers that are associated with neonatal growth may help reduce PGF and associated long-term morbidity.

OBJECTIVE

To investigate the associations between cord blood vascular endothelial growth factor (VEGF) and its soluble receptor (sFlt-1) with birth weight (BW) and postnatal growth in premature infants.

STUDY DESIGN AND METHODS

From an ongoing birth cohort, 123 premature infants from 23 to 36 weeks gestational age (GA) were studied. Cord blood plasma VEGF and sFlt-1 were measured via enzyme-linked immunoassay. Growth parameters and nutritional information were evaluated. Multivariate logistic regression models were constructed to evaluate the associations of VEGF and sFlt-1 on PGF, defined as weight <10th percentile at 36 weeks corrected age or discharge.

RESULTS

VEGF was positively correlated, and sFlt-1 was negatively correlated with BW and BW-for-GA percentiles. Higher cord blood VEGF levels were associated with reduced risk of PGF (OR=0.7; 95% CI=0.5-0.9), while higher sFlt-1 levels appeared to increase the risk of PGF (OR=1.6; 95% CI=1.1-2.4). The above biomarker associations were attenuated after adjustment for maternal preeclampsia, fetal growth restriction and related neonatal characteristics, and when taking into account placental vascular pathologies. Longitudinal growth patterns by mean weight and length percentiles were consistently lower among infants with low VEGF/sFlt-1 ratios.

CONCLUSIONS

Our data support that intrauterine regulation of angiogenesis is an important mechanism of fetal and postnatal growth. Cord blood VEGF and sFlt-1 are useful in elucidating how intrauterine processes may have long-standing effects on developing premature infants.

Biomarkers of endothelial dysfunction in preeclampsia and neonatal morbidity: a case-control study

OBJECTIVE

To investigate the association of preeclampsia with angiogenic imbalance, and the correlation of levels of angiogenic and anti-angiogenic factors to complications in mother and fetus.

STUDY DESIGN

Serum samples were obtained from 40 women with established preeclampsia (study group) and from 40 normotensive women (control group). Epidemiological characteristics of the two groups were analyzed. The levels of the angiogenic (VEGF and PlGF) and anti-angiogenic (sFlt-1) factors of the two study groups were determined in serum using ELISA. Neonatal adverse outcomes (late preterm, early term, low birth weight (LBW), very LBW (VLBW), intrauterine growth restriction (IUGR), and neonatal intensive care unit (NICU) admission) between the groups of the study were analyzed, as well as the association between the biomarkers of the study and neonatal adverse outcomes of the preeclamptic group of patients.

RESULTS

sFlt-1 levels were significantly higher in the preeclamptic women compared to normotensive women (median (range): 21297 (690-32637)pg/ml vs. 846.45 (363-2867)pg/ml, respectively), whereas there was a significant decrease in the levels of VEGF (90 (90-211)pg/ml vs. 90.55 (90-521)pg/ml, respectively), as well as in the levels of PlGF (13.62 (8-532)pg/ml vs. 239.86 (61-685)pg/ml, respectively). The increased serum values of the anti-angiogenic sFlt-1 were associated with increased rates of late preterm and early term births and VLBW.

CONCLUSION

An imbalance between angiogenic and anti-angiogenic factors exists in preeclampsia and is associated with adverse maternal and neonatal outcomes.

Vascular endothelial growth factor +936C/T, -634G/C, -2578C/A, and -1154G/A polymorphisms with risk of preeclampsia: a meta-analysis

BACKGROUND

Emerging evidence showed that VEGF gene polymorphisms are involved in the regulation of VEGF protein expression, thus increasing an individual's susceptibility to preeclampsia (PE); but individually published results are inconclusive. The aim of this meta-analysis was to investigate the associations between VEGF gene polymorphisms and PE risk.

METHODS

A systematic literature search of MEDLINE, Embase, Web of Science, and CNKI (Chinese National Knowledge Infrastructure) databases was conducted. Statistical analyses were performed using STATA 12.0 software and Review manager 5.1. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations.

RESULTS

According to the inclusion criteria, 11 case-control studies were finally included in this meta-analysis. A total of 1,069 PE cases and 1,315 controls were included in this study. Our meta-analysis indicated that VEGF +936C/T (T vs. C, OR = 1.52, 95%CI = 1.08-2.12) or -634G/C polymorphism (C vs. G, OR = 1.24, 95% CI = 1.03-1.50) was associated with the risk of PE, whereas there was no association between -2578C/A (A vs. C, OR = 0.98, 95%CI = 0.82-1.16) or -1154G/A (A vs. G, OR = 1.30, 95%CI = 0.94-1.78) polymorphism and PE risk in our study.

CONCLUSION

Our meta-analysis suggested that VEGF -2578C/A or -1154G/A polymorphism had no association with PE risk in all examined patients, whereas there was an association between VEGF +936C/T or -634G/C polymorphism and risk of PE.

First-trimester serum soluble fms-like tyrosine kinase-1, free vascular endothelial growth factor, placental growth factor and uterine artery Doppler in preeclampsia

OBJECTIVE

To compare the first-trimester serum concentrations of soluble fms-like tyrosine kinase-1 (sFlt-1), free vascular endothelial growth factor (free-VEGF), placental growth factor (PlGF), and uterine artery pulsatility index (PI) in women who later developed preeclampsia (PE).

STUDY DESIGN

Prospectively collected maternal serum samples were evaluated for sFlt-1, free VEGF, and PlGF levels in 63 cases who later developed PE compared with 252 unaffected controls. Serum levels of these angiogenic factors were measured using Quantikine immunoassays. Both univariate and multivariate analyses were used to evaluate the association between angiogenic factors and PE. The relationship between the angiogenic factors and mean maternal uterine artery PI was also evaluated.

RESULT

Maternal serum sFlt-1 levels were not significantly different between the cases and controls. Mean free-VEGF levels were significantly higher in women destined to develop PE compared with the controls (P=0.04), and mean PlGF levels were significantly lower in women who later developed PE (P=0.01). There was no significant correlation between maternal mean uterine artery PI and angiogenic factors evaluated. Receiver-operating characteristic curves revealed that none of the factors were clinically useful for prediction in the first trimester of PE.

CONCLUSION

Despite some significant differences in the first-trimester serum levels of angiogenic factors, our models suggest that these factors are not clinically useful for prediction in women who later developed PE.

Evidence of an imbalance of angiogenic/antiangiogenic factors in massive perivillous fibrin deposition (maternal floor infarction): a placental lesion associated with recurrent miscarriage and fetal death

OBJECTIVE

Massive perivillous fibrin deposition (MPFD) is associated with serious complications of pregnancy including recurrent spontaneous abortion, fetal growth restriction, and fetal demise. The aim of this study was to determine whether maternal plasma concentrations of angiogenic/antiangiogenic factors in MPFD differ from those of uncomplicated pregnancies.

STUDY DESIGN

This retrospective longitudinal case-control study included MPFD cases (n = 10) and control patients (n = 175) with uncomplicated pregnancies who were enrolled in a longitudinal study and delivered at term. Serial plasma concentrations of placental growth factor (PlGF), soluble endoglin (sEng), and soluble vascular endothelial growth factor receptor (sVEGFR)-1 and -2 were determined by an enzyme-linked immunosorbent assay (cases, n = 28 samples; controls, n = 723 samples). Individual analyte concentrations were averaged across gestational age at specimen collection intervals. Linear mixed models were used to test for differences in log-transformed mean analyte concentrations both overall and as a function of time.

RESULTS

The following results were found: (1) patients with MPFD had a lower mean plasma PlGF concentration (P = .03) and higher mean plasma concentrations of sVEGFR-1 and sEng (both P < .01) than controls, adjusted for potential confounders; (2) the mean plasma concentration of PlGF differed further among cases and controls as a function of gestational age interval (P < .0001); however, mean sVEGFR-1 and sEng group differences as a function of gestational age interval approached but did not reach significance (P = .09 and P = .11, respectively); (3) patients with MPFD had lower mean plasma concentrations of PlGF/sVEGFR-1 (P < .0001) and PlGF/sEng (P < .001): both of these relationships differed further as a function of gestational age interval (both P < .0001); and (4) differences in mean sVEGFR-1, sEng, and the ratios of PlGF to sVEGFR-1 and PlGF to sEng were observed before 20 weeks of gestation.

CONCLUSION

An imbalance of angiogenic/antiangiogenic factors is present in patients with MPFD prior to the diagnosis. We propose that these changes participate in the mechanisms responsible for adverse pregnancy outcomes in patients with MPFD.

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

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Pathogenesis of pre-eclampsia: marinobufagenin and angiogenic imbalance as biomarkers of the syndrome

Pre-eclampsia (preE), a pregnancy disorder with the de novo onset of hypertension and proteinuria after 20 weeks of gestation, has multiple triggers that initiate pathophysiologic mechanisms. This review addresses translational aspects of preE by synthesizing information on preE pathogenesis, describing diagnostic biomarkers that predict disease, and suggesting strategies to lessen adverse outcomes. Key to this understanding is the role of cardiotonic bufodienolides, with marinobufagenin (MBG) as the prototype, and angiogenic factors in preE pathogenesis. Data from a rat model believed to mimic human preE show that urinary excretion of MBG increases before the onset of hypertension and proteinuria and that affected animals have an increased vascular leakage and blood brain barrier permeability. Angiogenic imbalance occurs with the onset of the syndrome in this model. Also, we report that MBG levels in preE patients exceed those in normal pregnancy and that angiogenic factors are altered in patients showing signs and symptoms of overt disease. In vitro administration of MBG inhibits cytotrophoblast function and triggers hyperpermeability in endothelial cell monolayers. We advance the hypotheses that MBG precedes preE; MBG causes disruption of tight junction proteins leading to vascular leak via activation of MAPK which triggers apoptotic mechanisms resulting in further endothelial dysfunction leading to edema with the release of angiogenic factors. This review provides new evidence about the role of MBG and vasoactive intermediates in preE pathogenesis including the neurologic sequela and may reveal new therapeutic targets for the prevention of preE complications.

Magnesium sulfate therapy of preeclampsia: an old tool with new mechanism of action and prospect in management and prophylaxis

A disturbed balance between angiogenic and antiangiogenic growth factors is a highly accepted mechanism in the pathogenesis of pregnancy-induced hypertension and proteinuria, which is clinically known as preeclampsia (PE). We investigated the effect of magnesium sulfate (MgSO4) therapy on vascular endothelial growth factor (VEGF), placental growth factor (PlGF), nitric oxide (NO) metabolites, soluble fm-like tyrosine kinase-1 (sFlt-1) and endoglin levels in PE rats and the effect of this treatment on the feto-maternal outcome. The PE group showed hypertension, proteinuria and decreased number and weight of live pups relative to the control group. This result was associated with increased sFlt-1, VEGF receptor-2 (VEGFR-2), VEGFR-3 and endoglin levels but decreased NO metabolites. MgSO4 therapy ameliorated systolic hypertension and proteinuria and decreased sFlt-1, VEGFR-2, VEGFR-3 and endoglin levels but increased NO metabolites in the treated group. Physiological and biochemical changes and improved pup weight and viability were observed in the treated group. The vasodilator action of MgSO4 and increased NO production are expected to increase placental blood flow and help fetal nutrition and development. Relief of placental ischemia decreases the production of antiangiogenic growth factors and restores the bioavailability of angiogenic factors (PlGF and VEGF). These changes resulted in better fetal outcome and an improved clinical picture of PE. These findings are promising and encourage further study of the mechanism of action of MgSO(4) to support its widespread use in the prevention and management of the etiopathological changes underlying the vast majority of the manifestations and complications of PE.

An unexpected tail of VEGF and PlGF in pre-eclampsia

PET (pre-eclamptic toxaemia), characterized by pregnancy-related hypertension and proteinuria, due to widespread endothelial dysfunction, is a primary cause of maternal morbidity. Altered circulating factors, particularly the VEGF (vascular endothelial growth factor) family of proteins and their receptors, are thought to be key contributors to this disease. Plasma from patients with PET induces numerous cellular and physiological changes in endothelial cells, indicating the presence of a circulating imbalance of the normal plasma constituents. These have been narrowed down to macromolecules of the VEGF family of proteins and receptors. It has been shown that responses of endothelial cells in intact vessels to plasma from patients with pre-eclampsia is VEGF-dependent. It has recently been shown that this may be specific to the VEGF₁₆₅b isoform, and blocked by addition of recombinant human PlGF (placental growth factor). Taken together with results that show that sVEGFR1 (soluble VEGF receptor 1) levels are insufficient to bind VEGF-A in human plasma from patients with pre-eclampsia, and that other circulating macromolecules bind, but do not inactivate, VEGF-A, this suggests that novel hypotheses involving altered bioavailability of VEGF isoforms resulting from reduced or bound PlGF, or increased sVEGFR1 increasing biological activity of circulating plasma, could be tested. This suggests that knowing how to alter the balance of VEGF family members could prevent endothelial activation, and potentially some symptoms, of pre-eclampsia.

Angiogenic growth factors in the diagnosis and prediction of pre-eclampsia

The pathogenesis of pre-eclampsia is still not completely known; however, in the recent decade, there have been tremendous research efforts leading to impressive results highlighting the role of a disturbed angiogenic balance as one of the key features of the disease. Numerous studies have shown the key role of the placenta in the pathogenesis of pre-eclampsia. A shift in the sFlt-1 (soluble Fms-like tyrosine kinase-1)/PlGF (placental growth factor) ratio is associated with the disease. Although pre-eclampsia seems to be a clearly defined disease, clinical presentation, and particularly the dynamics of the clinical course, can vary enormously. The only available tools to diagnose pre-eclampsia are blood pressure measurement and urine protein sampling. However, these tools have a low sensitivity and specificity regarding the prediction of the course of the disease or maternal and perinatal outcomes. The only cure for the disease is delivery, although a timely diagnosis helps in decreasing maternal and fetal morbidity and mortality. The sFlt1/PlGF ratio is able to give additional valuable information on the status and progression of the disease and is apt to be implemented in the diagnostic algorithm of pre-eclampsia. In the present review, we aim to provide an overview of the vast literature on angiogenesis and anti-angiogenesis factors in pre-eclampsia that have been published over the last decade. We introduce work from basic research groups who have focused on the pathophysiological basis of the disease. Furthermore, we review studies with a clinical focus in which the sFlt-1/PlGF ratio has been analysed along with other candidates for routine clinical assessment of pre-eclampsia.

Endothelial-derived hyperpolarization factor (EDHF) contributes to PlGF-induced dilation of mesenteric resistance arteries from pregnant rats

The aim of this study was to investigate the cellular mechanism involved in the potent vasodilatory action of PlGF on mesenteric resistance arteries from pregnant rats. PlGF (3 nM) induced a vasodilation of 64 ± 3.8% that was completely abolished by endothelial denudation. Significant dilation (28 ± 4.0%) remained, however, in the presence of nitric oxide synthase and cyclooxygenase inhibition, and was associated with significant reductions in vascular smooth muscle cell calcium. Absence of dilation in potassium-depolarizing solution (30 mM) confirmed its dependence on endothelial-derived hyperpolarization factor. Subsequent studies established that vasodilation was abolished by pharmacologic inhibition of SK(Ca) (apamin) and BK(Ca) (iberiotoxin) but not IK(Ca) (tram-34) potassium channels. In summary, PlGF acts through the release of a combination of endothelium-derived relaxation factors. Based on the results of potassium channel blockade, we suggest that it induces endothelial hyperpolarization via SK(Ca) channel activation; this, in turn, leads to the release of a diffusible mediator that activates vascular smooth muscle BK(Ca) channels, hyperpolarization and vasodilation. This is the first study to identify the mechanism for PlGF/VEGFR-1 resistance artery dilation in the pregnant state, whose attenuation likely contributes to the systemic hypertension characteristic of pre- eclampsia.

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.

Circulating angiogenic and antiangiogenic factors in women with eclampsia

OBJECTIVE

The objective of the study was to determine whether eclampsia has a different circulating profile of angiogenic (placental growth factor [PlGF]) and antiangiogenic factors (soluble vascular endothelial growth factor receptor-1 [sVEGFR-1] and soluble endoglin [sEng]) from severe preeclampsia.

STUDY DESIGN

This cross-sectional study included pregnant women in the following groups: (1) normal pregnancy (n = 40); (2) severe preeclampsia (n = 40); and (3) eclampsia (n = 20). Maternal serum PlGF, sVEGFR-1, and sEng concentrations were determined using an enzyme-linked immunosorbent assay.

RESULTS

The study results included the following: (1) the median concentration of sVEGFR-1 and sEng was higher and of PlGF was lower in severe preeclampsia or eclampsia than in normal pregnancy (P < .001 for all); and (2) the median concentrations of these 3 analytes did not differ significantly between patients with severe preeclampsia and those with eclampsia.

CONCLUSION

Eclampsia is associated with higher maternal circulating concentrations of sVEGFR-1 and sEng and lower concentrations of PlGF than normal pregnancy but with similar concentrations to severe preeclampsia. These findings suggest that eclampsia shares a common pathogenic pathway as severe preeclampsia.

Circulating predictive biomarkers in preeclampsia

The aim of the paper was to review promising prediction biomarkers for preeclampsia. The methods included review of abstracts on PubMed, using "preeclampsia", "biomarker", "prediction" as key words, followed by review of primary papers investigating blood based biomarkers. Angiogenic factors, such as PlGf and sFlt1, and PP13 seem presently to have the best predictive test values for preeclampsia, but sensitivity and specificity is still too low to prove useful in a population screening setting. Biomarker testing should still be part of research protocols. Biomarkers could provide useful in selecting high-risk women for prophylactic trials as well as identifying pregnancies that could profit from closer follow-up.

Microbial invasion of the amniotic cavity in preeclampsia as assessed by cultivation and sequence-based methods

OBJECTIVE

Infection has been implicated in the pathogenesis of preeclampsia, yet the association between microbial invasion of the amniotic cavity (MIAC) and preeclampsia has not been determined. The aim of this study was to determine the prevalence, and microbial diversity associated with MIAC, as well as the nature of the host response to MIAC in patients with preeclampsia.

METHOD OF STUDY

Amniotic fluid (AF) from 62 subjects with preeclampsia, not in labor, was analyzed with both cultivation and molecular methods. Broad-range and group-specific PCR assays targeting small subunit ribosomal DNA, or other gene sequences, from bacteria, fungi and archaea were used. Results were correlated with measurements of host inflammatory response, including AF white blood cell count and AF concentrations of glucose, interleukin-6 (IL-6) and MMP-8.

RESULTS

1) The rate of MIAC in preeclampsia was 1.6% (1/62) based on cultivation techniques, 8% (5/62) based on PCR, and 9.6% (6/62) based on the combined results of both methods; 2) among the six patients diagnosed with MIAC, three had a positive PCR for Sneathia/Leptotrichia spp.; and 3) patients with MIAC were more likely to have evidence of an inflammatory response in the amniotic cavity than those without MIAC, as determined by a higher median AF IL-6 [1.65 ng/mL interquartile range (IQR): 0.35-4.62 vs. 0.22 ng/mL IQR: 0.12-0.51; P=0.002).

CONCLUSION

The prevalence of MIAC in preeclampsia is low, suggesting that intra-amniotic infection plays only a limited role in preeclampsia. However, the unexpectedly high number of positive AF specimens for Sneathia/Leptotrichia warrants further investigation.

Serum and plasma determination of angiogenic and anti-angiogenic factors yield different results: the need for standardization in clinical practice

OBJECTIVE

The importance of an anti-angiogenic state as a mechanism of disease in preeclampsia is now recognized. Assays for the determination of concentrations of soluble vascular endothelial growth factor receptor (sVEGFR)-1, sVEGFR-2, placental growth factor (PlGF) and soluble endoglin (sEng) have been developed for research and clinical laboratories. A key question is whether these factors should be measured in plasma or serum. The purpose of this study was to determine if there are differences in the concentrations of these analytes between plasma and serum in normal pregnancy and in preeclampsia.

METHODS

Samples of maternal blood were obtained by venipuncture and collected in EDTA (lavender top) and serum collection tubes (red top). A standard laboratory procedure was implemented for the centrifugation, aliquoting and storage of samples. Plasma and serum from 70 women with normal pregnancies and 34 patients with preeclampsia were assayed for sVEGFR-1, sVEGFR-2, PlGF and sEng by ELISA. Nonparametric paired tests were used for analyses.

RESULTS

A significant difference between plasma and serum concentration was observed for sVEGFR-1 and sVEGFR-2 in normal pregnancy, and for sVEGFR-1, sVEGFR-2, PlGF and sEng in women with preeclampsia.

CONCLUSION

The concentrations of sVEGFR-1, sVEGFR-2, PlGF and sEng when measured in maternal plasma and in serum are different. Therefore, the matrix used for the assay (serum versus plasma) needs to be considered when selecting thresholds for predictive studies and interpreting the growing body of literature on this subject.

Angiogenic imbalances: the obstetric perspective

Clinical and experimental evidence indicates that angiogenic imbalances may participate in the mechanisms of disease of several pregnancy complications, some of which may be life threatening. This article reviews current evidence in support of this view and the possibility that the fetus may play a central role in these imbalances; it also reviews recent experimental observations that modulation of angiogenic imbalances during pregnancy may have prophylactic and/or therapeutic value.

Preeclampsia and pregnancies with small-for-gestational age neonates have different profiles of complement split products

OBJECTIVE

The activation of the complement system results in the generation of split products with pro-inflammatory properties. The objective of this study was to determine whether preeclampsia and small-for-gestational age (SGA) are associated with changes in the maternal plasma concentrations of anaphylatoxins C3a, C4a and C5a.

METHODS

A cross-sectional study was conducted in the following groups: (a) normal pregnant women (n = 134); (b) women who delivered an SGA neonate (n = 53); (c) preeclampsia with (n = 52) and without SGA (n = 54). Maternal plasma anaphylatoxin concentrations were determined by enzyme-linked immunoassay.

RESULTS

(1) Women with preeclampsia with or without SGA had a significantly higher median plasma C5a concentration than that of normal pregnant women and those with SGA alone (all P < 0.01); (2) women with SGA alone did not have an increase in plasma C5a concentration; (3) in contrast, the median maternal plasma concentration of C4a was lower in women with preeclampsia and SGA than that of those with a normal pregnancy (P = 0.001); (4) no changes in C3a were observed among the study groups.

CONCLUSION

Preeclampsia is associated with increased plasma concentration of C5a, regardless of the presence or absence of an SGA fetus. In contrast, there was no difference in the plasma C3a, C4a and C5a concentration in patients with SGA.

Retinol binding protein 4--a novel association with early-onset preeclampsia

OBJECTIVE

Dysregulation of maternal circulating adipokines has been implicated in several "great obstetrical syndromes" including preeclampsia (PE), small-for-gestational age (SGA) neonate and fetal death (FD). It has been suggested that adipokines provide a molecular link between metabolic derangements and inflammatory response in complicated pregnancies. Retinol binding protein 4 (RBP4), a novel adipokine, plays a role in obesity-related disorders, as well as in the regulation of the immune response. The aim of this study was to determine whether there are changes in maternal plasma concentrations of RBP4 in patients with PE and in those with an SGA neonate or FD.

STUDY DESIGN

This cross-sectional study included patients in the following groups: 1) normal pregnancy (n=134); 2) PE (n=104); 3) SGA neonate (n=28); and 4) FD (n=37). Maternal plasma RBP4 concentrations were determined by ELISA. Non-parametric statistics were used for analysis.

RESULTS

1) The median maternal plasma RBP4 concentration was higher among patients with PE than in those with a normal pregnancy (P=0.03); 2) The median maternal plasma RBP4 concentrations of patients with preterm PE (<37 weeks) was higher than that of those with term PE (P=0.017) and than that of those with a normal pregnancy (P=0.002); 3) The median maternal plasma RBP4 concentration did not differ significantly between patients with a normal pregnancy and those with an SGA neonate or with an FD; 4) Among normal pregnant women, the maternal plasma RBP4 concentrations did not correlate with pre-pregnancy body mass index, gestational age at blood sampling and neonatal birthweight.

CONCLUSIONS

1) Preeclampsia, but not pregnancy with an SGA neonate or an FD, is associated with a higher median maternal plasma concentration of RBP4 than normal pregnancy; 2) Preterm PE, and specifically early-onset PE, is associated with higher median RBP4 concentrations in maternal plasma compared to term PE. These findings suggest a role for RBP4 in the pathogenesis of preterm PE, but not in SGA and FD.

Role of nutrition in the risk of preeclampsia

Preeclampsia (PE) accounts for about one-quarter of the cases of maternal mortality and ranks second among the causes of pregnancy-associated maternal deaths in Canada and worldwide. The identification of an effective strategy to prevent PE is a priority and a challenge for research in obstetrics. Progress has been hampered by inadequate understanding of the underlying etiology of the disease. The role of maternal diet in the etiology of PE has recently received increased attention. The objective of this paper is to provide an overview of the literature concerning 1) the current understanding of the pathogenesis of PE, 2) the biological plausibility and potential mechanisms underlying the associations between maternal dietary exposures, nutrition, and the risk of PE, and 3) the epidemiological findings of maternal nutrient intake in relation to the risk of PE.

Fetal and maternal angiogenic/anti-angiogenic factors in normal and preeclamptic pregnancy

Few studies evaluated angiogenic/anti-angiogenic factors and endothelial (dys)function in both maternal and umbilical cord blood (UCB) in preeclampsia (PE). We aimed to clarify the role of placental growth factor (PlGF), vascular endothelial growth factor (VEGF), soluble vascular endothelial growth factor receptor 1 (VEGFR-1) and tissue plasminogen activator (tPA), by evaluating them in maternal and UCB in 42 normal and 46 preeclamptic (PEc) cases. In PE, maternal and UCB PlGF were significantly lower; maternal VEGF, sVEGFR-1 and tPA were significantly higher. In UCB, sVEGFR-1 and tPA were significantly higher in PEc cases, while VEGF and PlGF were significantly lower. A significant correlation between maternal and UCB sVEGFR-1, and between sVEGFR-1 and tPA both in maternal and UCB, was observed in PEc cases. In maternal and UCB circulation in PE, a close interaction seems to exist between endothelial dysfunction and angiogenesis disturbance, and sVEGFR-1 seems to play a central role in those disturbances.

A prospective cohort study of the value of maternal plasma concentrations of angiogenic and anti-angiogenic factors in early pregnancy and midtrimester in the identification of patients destined to develop preeclampsia

OBJECTIVE

Changes in the maternal plasma concentrations of angiogenic (placental growth factor (PlGF) and vascular endothelial growth factor (VEGF)) and anti-angiogenic factors (sEng and vascular endothelial growth factor receptor-1 (sVEGFR-1)) precede the clinical presentation of preeclampsia. This study was conducted to examine the role of maternal plasma PlGF, sEng, and sVEGFR-1 concentrations in early pregnancy and midtrimester in the identification of patients destined to develop preeclampsia.

METHODS

This longitudinal cohort study included 1622 consecutive singleton pregnant women. Plasma samples were obtained in early pregnancy (6-15 weeks) and midtrimester (20-25 weeks). Maternal plasma PlGF, sEng, and sVEGFR-1 concentrations were determined using sensitive and specific immunoassays. The primary outcome was the development of preeclampsia. Secondary outcomes included term, preterm, and early-onset preeclampsia. Receiving operating characteristic curves, sensitivity, specificity, positive and negative likelihood ratios, and multivariable logistic regression were applied. A p-value of <0.05 was considered significant.

RESULTS

(1) The prevalence of preeclampsia, term, preterm, (<37 weeks) and early-onset preeclampsia (<34 weeks) was 3.8 (62/1622), 2.5 (40/1622), 1.4 (22/1622) and 0.6% (9/1622), respectively; (2) Higher likelihood ratios were provided by ratios of midtrimester plasma concentrations of PlGF, sEng, and sVEGFR-1 than single analytes; (3) Individual angiogenic and anti-angiogenic factors did not perform well in the identification of preeclampsia as a whole; in particular, they perform poorly in the prediction of term preeclampsia; (4) In contrast, a combination of these analytes such as the PlGF/sEng ratio, its delta and slope had the best predictive performance with a sensitivity of 100%, a specificity of 98-99%, and likelihood ratios for a positive test of 57.6, 55.6 and 89.6, respectively, for predicting early-onset preeclampsia.

CONCLUSIONS

(1) The PlGF/sEng ratio and its delta and slope had an excellent predictive performance for the prediction of early-onset preeclampsia, with very high likelihood ratios for a positive test result and very low likelihood ratios for a negative test result; and (2) Although the positive likelihood ratios are high and the positive predictive values low, the number of patients needed to be closely followed is 4:1 for the PlGF/sEng ratio and 3:1 for the slope of PlGF/sEng.

Vascular endothelial growth factor gene polymorphisms and pregnancy

Vascular endothelial growth factor (VEGF) is a major angiogenic factor and prime regulator of endothelial cell proliferation. During pregnancy, VEGF is essential for the proliferation of trophoblasts, the development of embryonic vasculature and the growth of maternal and fetal blood cells in utero. In cases of pre-eclampsia and in some circumstances of preterm labor-raised umbilical cord serum, VEGF levels might be correlated with the clinical development of the above pathological disorders. Genetic alteration as 936C/T VEGF gene polymorphism has a statistical significant correlation with the severity of pre-eclampsia. The same VEGF gene polymorphism, which has been associated with lower protein production, has an increased risk of spontaneous preterm delivery in a Greek-studied population. Homozygotes were found to carry the greatest risk with a lesser proportionate risk associated with heterozygosity, whereas women with the -1154 allele of the VEGF gene have an increased risk of recurrent pregnancy loss. In this review, we present evidence that demonstrates an implication of VEGF gene polymorphisms in the pathological disorders of pregnancy. However, further genetic studies are needed to confirm these data.

Plasma soluble vascular endothelial growth factor receptor-1 concentration is elevated prior to the clinical diagnosis of pre-eclampsia

OBJECTIVE

Accumulating evidence suggests that the balance between vascular endothelial growth factor (VEGF), placental growth factor (PIGF), and their receptors is important for effective vasculogenesis, angiogenesis, and placental development. Recently, the soluble form of VEGFR-1 (sVEGFR-1), an antagonist to VEGF and PIGF, has been implicated in the pathophysiology of pre-eclampsia. Plasma sVEGFR-1 concentration is elevated in pre-eclampsia at the time of clinical diagnosis and correlates with the severity of the disease. The purpose of this study was to determine whether the concentrations of sVEGFR-1 in plasma of pre-eclamptic patients change prior to the clinical manifestations of the disease.

METHODS

A longitudinal case-control study was conducted in normal pregnant women (n = 44) and patients with pre-eclampsia (n = 44). Blood sampling was performed at six intervals: (1) 7-16 weeks; (2) 16-24 weeks; (3) 24-28 weeks; (4)28-32 weeks; (5) 32-36 weeks; and (6) more than 37 weeks of gestation. To examine the relationship between plasmasVEGFR-1 concentration and interval to clinical diagnosis of pre-eclampsia, plasma samples of pre-eclamptic patients at different gestational ages were stratified according to the interval from blood sampling to clinical development of the disease into five groups: (1) at clinical manifestation; (2) 2-5 weeks; (3) 6-10 weeks; (4) 11-16 weeks; and (5) 17-25 weeks before clinical manifestations. Plasma concentrations of sVEGFR-1 were determined by enzyme-linked immunoassay. Parametric statistics and repeated measure procedures were used for the analysis.

RESULTS

The mean plasma sVEGFR-1 concentration in pre-eclamptic patients before the clinical manifestation of the disease was significantly higher than in normal pregnant women at 24-28, 28-32, and 32-37 weeks of gestation (p = 0.02,p < 0.001, and p < 0.001, respectively). In contrast, no significant differences in the mean plasma sVEGFR-1 concentration between patients with pre-eclampsia and normal pregnant women were observed both at 7-16 weeks and 16-24 weeks of gestation (p= 0.1 and p= 0.9). Similarly, the mean plasma sVEGFR-1 concentration was significantly higher in pre-eclamptic patients than in normal pregnant women at clinical manifestation, at 2-5 weeks (mean 3.8 weeks), and at 6-10 weeks (mean 8.2 weeks) prior to the development of clinical pre-eclampsia (p < 0.001, p < 0.001, and p = 0.002,respectively). Among patients with early-onset pre-eclampsia (defined as gestational age of 34 weeks or less), the mean plasma sVEGFR-1 concentration was significantly higher in pre-eclampsia (before clinical diagnosis) than in normal pregnant women at 24-28 (mean 26.4) weeks of gestation (p = 0.008). In contrast, among patients with the late-onset disease(defined as gestational age of more than 34 weeks), plasma sVEGFR-1 concentration in pre-clinical pre-eclampsia was significantly higher than in normal pregnant women at 28-32 (mean 30.2) weeks of gestation (p < 0.001).

CONCLUSIONS

Plasma sVEGFR-1 concentration is elevated in pre-eclampsia prior to the clinical diagnosis of the disease. This elevation began 6-10 weeks prior to the clinical manifestations, and the increase was more pronounced at 2-5 weeks before the diagnosis, as well as at clinical presentation. Furthermore, in early-onset pre-eclampsia, plasma concentration ofsVEGFR-1 is elevated earlier than the late-onset disease.

Vascular endothelial growth factor attenuates Nomega-nitro-L-arginine methyl ester-induced preeclampsia-like manifestations in rats

OBJECTIVES

To verify the hypothesis that vascular endothelial growth factor (VEGF) attenuates Nomega-Nitro-L-arginine Methyl Ester (L-NAME)-induced preeclampsia-like manifestations in rats.

STUDY DESIGN

Forty pregnant Wistar rats were randomly divided into four groups: control, preeclampsia model, VEGF treatment, and VEGF prophylactic. On day 5 of gestation, L-NAME was injected subcutaneously in rats of the preeclampsia model, VEGF treatment, and VEGF prophylactic groups. VEGF was given after the occurrence of hypertension and proteinuria in the VEGF treatment group and from day 5 in the VEGF prophylactic group. Blood pressure was monitored and urine protein was assayed. Blood platelet was counted, and serum nitric oxide metabolites, endothelin-1, 6-keto-PGF-1alpha, and TXB2 were determined.

RESULTS

Blood pressure increased significantly on day 8 of gestation in the preeclampsia model and VEGF treatment groups compared with control (p < 0.05 for both) and remained elevated through the pregnancy in the preeclampsia model group. Blood pressure was significantly decreased after the administration of VEGF in the VEGF treatment group (p < 0.05). There was no significant difference in blood pressure between the VEGF prophylactic group and control (p > 0.05). Urine protein, platelet count, serum nitric oxide metabolites, endothelin-1, 6-keto-PGF-1alpha, and TXB2 were significantly different between control and the preeclampsia model group (p < 0.05), but not between control and the VEGF treatment or VEGF prophylactic groups (p > 0.05 for all).

CONCLUSION

VEGF attenuates L-NAME-induced preeclampsia-like manifestations in rats, suggesting the important role of VEGF in preeclampsia and providing a potential strategy for the prevention and treatment of preeclampsia.

Maternal serum adiponectin multimers in preeclampsia

OBJECTIVE

Obesity, insulin resistance, and dyslipidemia are associated with preeclampsia. Recently, "adipose tissue failure", characterized by dysregulation of adipokine production, has been implicated in the pathophysiology of these metabolic complications. Adiponectin, an insulin-sensitizing, anti-atherogenic, anti-inflammatory and angiogenic adipokine, circulates in oligomeric complexes including: low-molecular-weight (LMW) trimers, medium-molecular-weight (MMW) hexamers and high-molecular-weight (HMW) isoforms. These multimers exert differential biological effects, and HMW to total adiponectin ratio (S(A)) has been reported to be a specific marker of adiponectin activity. The aim of this study was to determine whether preeclampsia is associated with changes in circulating adiponectin multimers.

STUDY DESIGN

This cross-sectional study included women with: 1) normal pregnancy (n=225); and 2) patients with mild preeclampsia (n=111). The study population was further stratified by first trimester BMI (normal weight <25 kg/m(2) vs. overweight/obese >or=25 kg/m(2)). Serum adiponectin multimers (total, HMW, MMW and LMW) concentrations were determined by ELISA. Non-parametric statistics were used for analysis.

RESULTS

1) The median maternal HMW and LMW adiponectin concentrations were lower in patients with preeclampsia than in those with normal pregnancies (P<0.001 and P=0.01, respectively); 2) patients with preeclampsia had a lower HMW/total adiponectin ratio (P<0.001) and higher MMW/total adiponectin and LMW/total adiponectin ratios than those with a normal pregnancy (P<0.001 and P=0.009, respectively); 3) the presence of preeclampsia was independently associated with lower maternal serum HMW adiponectin concentrations (P=0.001) and with a low HMW/total adiponectin ratio (P<0.001) after correction for maternal age, maternal BMI, the difference in BMI between the third and the first trimester, and gestational age at sampling; and 4) overweight/obese pregnant women had a lower median total and HMW adiponectin concentration than normal weight pregnant women among women with normal pregnancies, but not among those with preeclampsia.

CONCLUSION

1) Preeclampsia is associated with a lower median concentration of the HMW adiponectin isoform, the most active form of this adipokine, and a low HMW/total adiponectin ratio, a specific marker of adiponectin biologic activity; 2) in contrast to normal pregnancy, preeclampsia is not associated with decreased circulating adiponectin multimers in overweight/obese individuals suggesting altered regulation of this adipokine in preeclampsia; 3) collectively, these findings suggest that preeclampsia is characterized by alterations in adiponectin multimers and their relative distribution implying a role for adiponectin multimers in the mechanism of disease in preeclampsia.