Placental growth factor and vascular endothelial growth factor serum levels in Tunisian Arab women with suspected preeclampsia

Discovery and verification of extracellular microRNA biomarkers for diagnostic and prognostic assessment of preeclampsia at triage

We report on the identification of extracellular miRNA (ex-miRNA) biomarkers for early diagnosis and prognosis of preeclampsia (PE). Small RNA sequencing of maternal serum prospectively collected from participants undergoing evaluation for suspected PE revealed distinct patterns of ex-miRNA expression among different categories of hypertensive disorders in pregnancy. Applying an iterative machine learning method identified three bivariate miRNA biomarkers (miR-522-3p/miR-4732-5p, miR-516a-5p/miR-144-3p, and miR-27b-3p/let-7b-5p) that, when applied serially, distinguished between PE cases of different severity and differentiated cases from controls with a sensitivity of 93%, specificity of 79%, positive predictive value (PPV) of 55%, and negative predictive value (NPV) of 89%. In a small independent validation cohort, these ex-miRNA biomarkers had a sensitivity of 91% and specificity of 57%. Combining these ex-miRNA biomarkers with the established sFlt1:PlGF protein biomarker ratio performed better than either set of biomarkers alone (sensitivity of 89.4%, specificity of 91.3%, PPV of 95.5%, and NPV of 80.8%).

Evaluation of the angiogenic factors sFlt-1, PlGF, and the sFlt-1/PlGF ratio in preeclampsia and associated features

PROBLEM

Soluble Fms-like tyrosine kinase-1 (sFLT-1) and placental growth factor (PlGF) were previously reported to play a key role in the pathogenesis of preeclampsia (PE). We tested the link between altered PlGF and sFLT-1 levels, and their ratio (sFlt-1/PlGF) with PE and PE-associated featured in Tunisian PE cases and age- and BMI-matched normotensive women.

METHOD OF STUDY

Peripheral blood specimens from 88 women with PE, and 60 control women were tested for PlGF and sFLT by commercially available ELISA.

RESULTS

Significant increases in sFlt-1 levels and in the sFlt-1/PlGF ratio, more than changes in PlGF levels were noted in PE subjects when compared to control women. Elevation in sFlt-1 and sFlt-1/PlGF ratio was observed at different percentile values in PE cases. The receiver operating characteristic (ROC) area under the curve (AUC) for sFlt-1, PlGF, and sFlt-1/PlGF ratio were 0.869 ± 0.031, 0.463 ± 0.048, and 0.759 ± 0.039, respectively. A systematic shift in sFlt-1, but not in PlGF, distributions for higher values occurred in PE subjects. A progressive increase in the adjusted OR paralleled increased sFlt-1 and the sFlt-1/PlGF ratio percentile values; no similar trend was noted for the PlGF percentiles. Increased sFlt-1 levels and sFlt-1/PlGF ratio were significantly correlated with dysmenorrhea, hypertension, baby weight, and C-section. In contrast, no correlation was found between PlGF and the PE-associated features tested.

CONCLUSIONS

Increased sFlt-1 levels and corresponding sFlt-1/PlGF ratio, but not circulating PlGF levels, constitute an independent risk factor for PE.

Preeclampsia is associated with reduced renin, aldosterone, and PlGF levels, and increased sFlt-1/PlGF ratio, and specific angiotensin-converting enzyme Ins-Del gene variants

We investigated the association of angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism with preeclampsia (PE) in Tunisian women. ACE I/D genotyping was done by PCR in 342 pregnant women with PE and 289 healthy pregnant women. The association between ACE I/D and PE and associated features were also evaluated. Decreased active renin concentration, plasma aldosterone concentration, and placental growth factor (PlGF) were observed in PE cases, while soluble fms-like tyrosine kinase-1 (sFlt-1)/PlGF ratio was significantly higher in the PE group. Distribution of ACE I/D alleles and genotypes were comparable between women with PE and control women. A significant difference in the frequency of the I/I genotype was seen between PE cases and control women according to the recessive model, with a trend towards association in the codominant model. Carriers of the I/I genotype had significantly higher infant birth weights compared to the I/D and the D/D genotype carriers. A dose-dependent relationship was also seen in VEGF and PlGF plasma levels and specific ACE I/D genotypes, with the lowest VEGF levels seen in the I/I genotype carriers compared to the D/D genotype carriers. Similarly, the I/I genotype carriers had the lowest PlGF levels compared to I/D and D/D genotype carriers. Furthermore, when studying the linkage between PE features, we found a positive correlation between PAC and PIGF. Our study suggests a role for ACE I/D polymorphism in the pathogenesis of PE, possibly through modulating VEGF and PlGF levels and infant birth weight, and highlights the relationship between PAC and PlGF.

MMP-2 and MMP-9 Polymorphisms and Preeclampsia Risk in Tunisian Arabs: A Case-Control Study

The abnormal production of matrix metalloproteinases (MMPs), especially MMP-9 and MMP-2, plays a pivotal role in hypertensive disorders of pregnancy, and as such, can influence the development of preeclampsia. These alterations may result from functional genetic polymorphisms in the promoter region of MMP-9 and MMP-2 genes, which modify MMP-9 and MMP-2 expression. We investigated the association of MMP-9 polymorphism rs3918242 (-1562 C>T) and MMP-2 polymorphism rs2285053 (-735 C>T) with the risk of preeclampsia. This case–control study was conducted on 345 women with preeclampsia and 281 age-matched women with normal pregnancies from Tunisian hospitals. Genomic DNA was extracted from whole blood collected at delivery. Genotypes for -1562 C>T and -735 C>T polymorphisms were performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). An increased frequency of heterozygous MMP-9 -1562 C/T genotype carriers was observed in women with preeclampsia compared to healthy controls (p = 0.03). In contrast, the MMP-2 -735 C>T polymorphism was not significantly different regarding frequency distribution of the allele and genotype between healthy pregnant women and women with preeclampsia. Our study suggests that the MMP-9 -1562 C/T variant, associated with high MMP-9 production, could be a genetic risk factor for preeclampsia in Tunisian women.

Circulating levels of angiogenic factors and their association with preeclampsia among pregnant women at Mulago National Referral Hospital in Uganda

Preeclampsia (PE) is a major cause of maternal and new-born morbidity and mortality. Angiogenic factors contribute a major role in the vascular dysfunction associated with PE. We investigated the circulating levels of vascular endothelial growth factor (VEGF), placental growth factor (PlGF) and soluble Feline McDonough Sarcoma (fms)-like tyrosine kinase-1 (sFlt1), their association with PE and diagnostic performance of disease among pregnant women in Uganda. Using a case-control study design, 106 women with PE and 106 with normal pregnancy were enrolled. Demographic and clinical characteristics, and anticoagulated blood samples were collected from participants. Plasma VEGF, PlGF and sFlt1 levels were measured using Luminex and enzyme linked immunosorbent assays (ELISA). Conditional logistic regression was used to explore association of angiogenic factors with PE and receiver operating characteristic analysis was performed to investigate PE diagnostic performance. Levels of VEGF and PIGF were significantly lower in cases compared to controls (VEGF: median = 0.71 pg/ml (IQR = 0.38-1.11) Vs 1.20 pg/ml (0.64-1.91), p-value<0.001 and PlGF: 2.20 pg/ml (1.08-5.86) Vs 84.62 pg/ml (34.00-154.45), p-value<0.001). Plasma levels of sFlt1 were significantly higher in cases than controls (median = 141.13 (71.76-227.10) x103 pg/ml Vs 19.86 (14.20-29.37) x103 pg/ml). Increasing sFlt1 levels were associated with increased likelihood of PE (aOR = 4.73; 95% CI, 1.18-19.01; p-value = 0.0287). The sFlt1/PlGF ratio and sFlt1 had a better performance for diagnosis of PE, with AUC = 0.95 (95% CI, 0.93-0.98) followed by PlGF with AUC = 0.94 (95% CI, 0.91-0.97). Therefore, sFlt1, sFlt1/PlGF ratio and PlGF are potential candidates for incorporation into algorithms for PE diagnosis in the Ugandan population.

Differential upregulations of SMAC and LAMIN B levels in the buffy coat of HIV associated preeclamptic women

OBJECTIVE

To assess HIV positivity as an apoptotic confounding variable in pregnancies complicated by preeclampsia.

METHODS AND MATERIALS

Using a Bio-plex Multiplex Immunoassay, Smac and Lamin B concentrations (ng/ml) were analyzed in a buffy coat collected from 128 pregnant women attending a large regional hospital in Durban, South Africa. Study groups consisted of Normotensive and Preeclamptic pregnant women stratified according to their HIV status. All HIV positive groups received highly active antiretroviral therapy (HAART).

RESULTS

Our findings showed significant (p < .05) upregulation in the levels of both SMAC and LAMIN B in the HIV positive patients and a concomitant downregulation of the same apoptotic makers were observed in preeclampsia regardless of HIV status.

CONCLUSIONS

These results could be associated with the fact that apoptosis promotes deregulation of mitochondrial dynamics, contributing to the associated severe obstetric events observed in pregnancies among HIV-infected women on HAART.

Immune and Apoptosis Mechanisms Regulating Placental Development and Vascularization in Preeclampsia

Preeclampsia is the most severe type of hypertensive disorder of pregnancy, affecting one in 10 pregnancies worldwide and increasing significantly maternal and neonatal morbidity and mortality. Women developing preeclampsia display an array of symptoms encompassing uncontrolled hypertension and proteinuria, with neurological symptoms including seizures at the end of pregnancy. The main causes of preeclampsia are still unknown. However, abnormal placentation and placenta vascularization seem to be common features in preeclampsia, also leading to fetal growth restriction mainly due to reduced placental blood flow and chronic hypoxia. An over activation of maternal immunity cells against the trophoblasts, the main cells forming the placenta, has been recently shown as an important mechanism triggering trophoblast apoptosis and death. This response will further disrupt the remodeling of maternal uterine arteries, in a first stage, and the formation of new placental vessels in a later stage. A consequent chronic hypoxia stress will further contribute to increase placental stress and exacerbate systemic circulatory changes in the mother. The molecular mechanisms driving these processes of apoptosis and anti-angiogenesis are also not well-understood. In this review, we group main evidences suggesting potential targets and molecules that should be better investigated in preeclampsia. This knowledge will contribute to improve therapies targeting a better placenta formation, having a positive impact on maternal disease prevention and on fetal development.

The Role of Placental Growth Factor, Soluble Endoglin, and Uterine Artery Diastolic Notch to Predict the Early Onset of Preeclampsia

BACKGROUND:

Reducing maternal mortality is one of the targets in the Millennium Development Goals (MDGs). In a systematic review, 4.6 per cent (95% CI 2.7-8.2) of pregnancies were complicated by preeclampsia worldwide. Preeclampsia occurs in around 10% of pregnancies in the world whereas developing countries contribute more than developed countries. In developing countries, there are 13 cases of preeclampsia in every 1,000 births, whereas in developed countries only 2-3 cases of preeclampsia are found in every 10,000 deliveries. Variations in prevalence among countries reflect, at least in part, differences in the distribution of maternal age and the proportion of nulliparous pregnant women in the population.

AIM:

We aimed to investigate the role of placental growth factor, soluble endoglin, and uterine artery diastolic notch to predict the early onset of preeclampsia.

METHODS:

This study used an analytical study with a nested case-control design. The study was conducted at Bunda Thamrin Hospital, Tanjung Mulia Mitra Medika Hospital, Sundari Hospital and a private clinic, from March to November 2018 with a total sample of 70 research subjects.

RESULTS:

Uterine artery diastolic notch was not found in 50% of subjects. A total of 27 subjects (38.6%) had a unilateral diastolic notch, and 8 subjects (11.4%) had a bilateral diastolic notch. Cut-off point PIGF levels was 441 pg/ml, and Area Under Curve (AUC) 82.5% (95% CI 61.5%-100%), with sensitivity 80% and specificity 87.7%. The levels sEng in this study could not predict the incidence of early-onset preeclampsia (p = 0.113). Combined PlGF and pulsatile index of uterine arteries may predict early onset preeclampsia with sensitivity 40% and specificity 90.77%. From these results, pregnant women o 22-24 weeks of pregnancy, the levels of PlGF and the uterine artery pulsatility index can be a predictor of early-onset preeclampsia. Examination of PlGF levels alone is sufficient as a predictor of early-onset preeclampsia.

CONCLUSION:

From these results, it can be concluded that in pregnant women of 22-24 weeks, the diastolic notches in uterine arteries cannot predict the incidence of early-onset preeclampsia. PlGF levels and pulsatile index of uterine arteries can be used as predictors of early-onset preeclampsia although examination of PlGF levels alone is sufficient as a predictor of early-onset preeclampsia.

Contribution of angiotensinogen M235T and T174M gene variants and haplotypes to preeclampsia and its severity in (North African) Tunisians

BACKGROUND

Preeclampsia (PE) is a pregnancy-associated hypertensive disorder and a leading cause of maternal and neonatal morbidity and mortality. While its pathogenesis remains ill defined, several candidate genes for PE have been identified, but results remain inconclusive. We investigated the association of the angiotensinogen ( AGT) gene variants M235T and T174M with PE, and we analyzed the contribution of both variants to the severity of PE.

METHODS

This case-control study enrolled 550 Tunisian pregnant women: 272 with PE, of whom 147 presented with mild, and 125 with severe PE, along with 278 unrelated age- and ethnically matched control women. AGT genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

Significantly higher M235T minor allele frequency (MAF) was associated with increased risk of PE ( p < 0.001). Decreased frequency of heterozygous T174M genotype carriers were found in control women ( p = 0.015), suggesting a protective effect of this genotype (odds ratio (95% confidence interval) = 0.51 (0.29-0.89)). Two-locus haplotype analysis demonstrated MM and TT haplotypes to be negatively and positively associated with PE, respectively. MAF of M253T, but not T174M, was higher in the severe PE group, and carrying M235T or T174M minor allele was associated with increased body mass index ( p < 0.001) among unselected PE women.

CONCLUSIONS

AGT M235T and T174M variants contribute to an increased risk of developing PE, and for M235T to PE severity.

Relaxin-2 connecting peptide (pro-RLX2) levels in second trimester serum samples to predict preeclampsia

OBJECTIVES

Preeclampsia is a serious complication of pregnancy, threatening fetal and maternal health. The aim of our study is to examine the association between preeclampsia and the connecting peptide of the pregnancy hormone relaxin (pro-RLX2) as a potential new biochemical marker.

STUDY DESIGN

This is a nested case/control study derived from the cohort of pregnancies delivering at Women & Infants Hospital. Cases were identified at a clinic or by hospital codes, and individually confirmed by record review. Stored samples were available from 'integrated' Down syndrome screening. Results were expressed as multiples of the median (MoM).

MAIN OUTCOME MEASURES

Preeclampsia was classified as early/severe, late/severe, or mild based on professional guidelines.

RESULTS

Fifty-one cases were each matched with five control pregnancies. Population distribution parameters were derived for cases and controls. As shown previously, discrimination between cases and controls (applying MoM analysis) was possible for PlGF (0.576, p < .05), inhibin A (1.45, p < .05) and endoglin (1.278, p < .05). No association with preeclampsia was found for pro-RLX2. However, pro-RLX2 correlates with Inhibin A and Endoglin.

CONCLUSIONS

Endoglin, Inhibin A and PlGF are highly predictive of preeclampsia. Quantification of pro-RLX2 is not able to predict preeclampsia. Nevertheless, the potential involvement of relaxin 2/pro-RLX2 in the pathophysiology of preeclampsia requires further study.

Decreased PGF may contribute to trophoblast dysfunction in fetal growth restriction

Fetal growth restriction (FGR) threatens perinatal health and is correlated with increased incidence of fetal original adult diseases. Most cases of FGR were idiopathic, which were supposed to be associated with placental abnormality. Decreased circulating placental growth factor (PGF) was recognized as an indication of placental deficiency in FGR. In this study, the epigenetic regulation of PGF in FGR placentas and the involvement of PGF in modulation of trophoblast activity were investigated. The expression level of PGF in placental tissues was determined by RT-qPCR, immunohistochemistry and ELISA. DNA methylation profile of PGF gene was analyzed by bisulfite sequencing. Trophoblastic cell lines were treated with ZM-306416, an inhibitor of PGF receptor FLT1, to observe the effect of PGF/FLT1 signaling on cell proliferation and migration. We demonstrated that PGF was downregulated in placentas from FGR pregnancies compared with normal controls. The villous expression of PGF was positively correlated with placental and fetal weight. The CpG island inside PGF promoter was hypomethylated without obvious difference in both normal and FGR placentas. However, the higher DNA methylation at another CpG island downstream exon 7 of PGF was demonstrated in FGR placentas. Additionally, we found FLT1 was expressed in trophoblast cells. Inhibition of PGF/FLT1 signaling by a selective inhibitor impaired trophoblast proliferation and migration. In conclusion, our data suggested that the PGF expression was dysregulated, and disrupted PGF/FLT1 signaling in trophoblast might contribute to placenta dysfunction in FGR. Thus, our results support the significant role of PGF in the pathogenesis of FGR.

Vascular endothelial growth factor single nucleotide polymorphisms and haplotypes in pre-eclampsia: A case-control study

An association between vascular endothelial growth factor (VEGFA) gene variants and altered VEGF secretion and preeclampsia (PE) were described, often with inconclusive findings. An ethnic contribution to the association of VEGFA polymorphisms with PE and its associated features was also suggested. To investigate whether common VEGFA single nucleotide polymorphisms (SNP) are linked with PE and associated features in Tunisian women. A case-control study involving 300 women with PE, and 300 age-matched control women. Genotyping of VEGFA rs833052, rs699947, rs833061, rs1570360, rs2010963, rs25648, rs833068, rs833070, rs3025020, and rs3025039SNPs was done by real-time PCR. Minor allele frequency (MAF) of rs833052, rs699947, rs833061, rs1570360, rs2010963, rs25648, rs833068, rs833070, rs3025020, and rs3025039 VEGFA SNP, were not significantly different between PE cases and control women. In addition, there was lack of association of the genotypes of VEGFA SNPs with PE, irrespective of the genetic model used. Seven-locus (rs699947, rs833061, rs1570360, rs2010963, rs25648, rs833068 and rs833070) haplotype analysis demonstrated positive association of ATGCCAA, ACAGCAG and CCAGCGG, and negative association of CCAGCAA and ATGCCGG haplotypes with PE, all of which except for ACAGCAG remained associated with PE after correcting for multiple comparisons. Increased and reduced PE severity was associated with ATGCCAA, and with ATGCCGG and CCAGCAA haplotypes, respectively. Furthermore, carriage of CCGGTAG haplotype was associated with reduced risk of PE. Our study suggests that VEGFA haplotypes, more so than individual SNPs, play a role in PE pathogenesis in Tunisian women. These findings need confirmation in other ethnic populations.

Serum biomarkers combined with uterine artery Doppler in prediction of preeclampsia

First-trimester screening may be a major advantage over a second-trimester approach since it opens prospects for early and more efficient interventions. The aim of the current study was to evaluate whether the measurement of maternal serum inhibin A, activin A and placental growth factor (PlGF) at three to four months gestation with the second-trimester uterine artery pulsatility index (PI) are useful in predicting preeclampsia in a group of nulliparous women. All the patients also underwent uterine artery Doppler examination to measure the PI at 22–24 weeks gestation. Inhibin A, activin A and PlGF were measured using an ELISA by an examiner who was blinded to the pregnancy outcome. Thirty-eight cases with preeclampsia and 100 controls were analyzed. Second-trimester uterine artery PI and marker levels were expressed as multiples of the median (MoM). The uterine artery PI was increased in pregnancies with preeclampsia compared with controls. In pregnancies that developed preeclampsia, the uterine artery PI was increased (1.61±0.047 vs. 1.02±0.049, P<0.001), as was the level of inhibin A (1.72±0.023 vs. 1.03±0.063, P<0.001) and the level of activin A (1.68±0.38 vs. 1.06±0.42, P<0.001) compared with the controls. In contrast, the level of PlGF was decreased in pregnancies that developed preeclampsia compared with the controls (0.69±0.23 vs. 1.00±0.26, P<0.001). A combination of activin A, PlGF and uterine artery PI gave an AUC of 0.915 (95% CI, 0.812–0.928; P<0.001) with a sensitivity of 91% at a specificity of 82%. In our study, we demonstrated that both serum inhibin A and activin A levels were increased, while the PlGF level was decreased in the early second-trimester in women who developed preeclampsia.