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OBJECTIVE

To test the hypothesis that high circulating concentrations of maternal anti-angiogenic factors are associated with increased risk of respiratory distress syndrome (RDS).

STUDY DESIGN

This is a nested case-control study of nulliparous women who delivered less than 37 weeks of gestation within the Calcium for Preeclampsia Prevention (CPEP) trial. The study included 116 women with preeclampsia or gestational hypertension and 323 normotensive controls. Soluble fms-like tyrosine kinase 1 (sFlt1), placental growth factor [PlGF] and soluble endoglin [sEng] in maternal serum were measured at 21–32 weeks of gestation.

RESULTS

Preterm infants born to hypertensive mothers were more likely to develop RDS (22.5 % versus 20.9%, P=0.03). After adjustment for gestational age at delivery, the odds ratio for the relationship between hypertension in pregnancy and RDS was 2.18 (95% C.I. 1.08, 4.39). In hypertensive pregnancies women whose infants developed RDS had significantly higher circulating mean sFlt1 levels during mid-pregnancy (21–32 weeks of gestation) even after adjustment for gestational age at delivery (21,516 pg/mL versus 7,000 pg/mL, P = 0.01).

CONCLUSIONS

Preterm preeclampsia and gestational hypertension, characterized by high circulating levels of sFlt1, are associated with a twofold increased risk of RDS in infants delivered before 37 weeks. Among women with these hypertensive pregnancies circulating sFlt1 concentrations during mid-pregnancy were substantially higher in women whose infants developed RDS.

BACKGROUND

Preeclampsia is considered a disease of immunological origin associated with abnormalities in inflammatory cytokines, tumor necrosis factor-α (TNF-α), and activated lymphocytes secreting AT1-AA. Recent studies have also demonstrated that an imbalance of angiogenic factors, soluble fms-like tyrosine kinase (sFlt-1), and sEndoglin, exists in preeclampsia; however, the mechanisms that initiate their overproduction are unclear.

METHODS

To determine the role of immune regulation of these factors, circulating and placental sFlt-1 and/or sEndoglin was examined from pregnant rats chronically treated with TNF-α or AT1-AA. On day 19 of gestation blood pressure was analyzed and serum and tissues were collected. Placental villous explants were excised and cultured on matrigel coated inserts for 24 h and sFlt-1 and sEndoglin was measured from media.

RESULTS

In response to TNF-α-induced hypertension, sFlt-1 increased from 180 ± 5 to 2,907 ± 412 pg/ml. sFlt-1 was also increased from cultured placental explants of TNF-α induced hypertensive pregnant rats (n = 12) (2,544 ± 1,132 pg/ml) vs. explants from normal pregnant (NP) rats (n = 12) (2,189 ± 586 pg/ml) where as sEng was undetectable. Circulating sFlt-1 increased from 245 ± 38 to 3,920 ± 798 pg/ml in response to AT1-AA induced hypertension. sFlt-1 levels were higher (3,400 ± 350 vs. 2,480 ± 900 pg/ml) in placental explants from AT1-AA infused rats (n = 12) than NP rats (n = 7). In addition, sEndoglin increased from 30 ± 2.7 to 44 ± 3.3 pg/ml (P < 0.047) in AT1-AA infused rats but was undetectable in the media of the placental explants.

CONCLUSIONS

These data suggest that immune factors may serve as an important stimulus for both sFlt-1 and sEndoglin production in response to placental ischemia.

Objective

The objective of the study was to determine whether blood pressure increases are associated with maternal angiogenic factors in uncomplicated and preeclamptic pregnancies.

Study Design

Associations of blood pressure increases from mid- to late pregnancy with maternal serum concentrations of soluble fms-like tyrosine kinase receptor (sFlt1), soluble endoglin (sEng), and placental growth factor (PlGF) at delivery were analyzed in 43 uncomplicated and 44 preeclamptic pregnancies.

Results

In uncomplicated pregnancies, increases in diastolic and mean arterial pressure were inversely associated with PlGF at delivery and positively associated with sEng and sFlt1/PlGF ratio. There were no significant associations between blood pressure increases and angiogenic factor concentrations in preeclampsia.

Conclusion

These data suggest that angiogenic factors are involved in blood pressure modulation in normotensive pregnancy and are consistent with the hypothesis that angiogenic balance plays a role in maternal breast cancer risk reduction associated with mid- to late blood pressure increases in uncomplicated pregnancies.

Background

Differences in circulating concentrations of antiangiogenic factors sFlt1 and soluble endoglin (sEng) and the pro-angiogenic growth factor PlGF are reported to precede the onset of preeclampsia weeks to months in low-risk pregnant women. The objective of this study was to investigate whether similar changes can be detected in pregnant women at high-risk to develop the syndrome.

Methods

This study is a secondary analysis of the NICHD MFMU trial of aspirin to prevent preeclampsia in high-risk pregnancies. Serum samples were available from 194 women with pre-existing diabetes, 313 with chronic hypertension, 234 with multifetal gestation, and 252 with a history of preeclampsia in a previous pregnancy. Samples collected across pregnancy were analyzed in a blinded fashion for sFlt1, sEng and PlGF.

Results

The odds of developing preeclampsia were significantly increased among women with multiple fetuses for each 2-fold elevation in sFlt1, sEng and the ratio of angiogenic factors (e.g. OR 2.18, 95% CI 1.46-3.32), and significantly decreased for each 2-fold elevation in circulating PlGF (OR 0.50, 95% CI 0.30-0.82) between 7 and 26 weeks' gestation. Cross-sectional analysis of the angiogenic factors across gestation showed significant differences during the third trimester in women who develop preeclampsia compared with appropriate controls in all high-risk groups. However, when data were examined in relation to the gestational week when preeclampsia was diagnosed only sFlt1 was significantly higher 2 to 5 weeks before the clinical onset of preeclampsia and only in women with previous preeclampsia.

Conclusions

The pattern of elevated concentrations of sFlt1 and sEng, and low PlGF in high-risk pregnant subjects who develop preeclampsia is similar to that reported in low-risk pregnant women. However, differences in these factors among high-risk women who do and do not develop preeclampsia are modest, and do not appear to be clinically useful predictors in these high-risk pregnant women.

Objective

Changes in maternal concentrations of the anti-angiogenic factors, soluble fms-like tyrosine kinase 1 (sFlt1) and soluble endoglin (sEng), and the pro-angiogenic placental growth factor (PlGF) precede the development of preeclampsia in healthy women. The risk of preeclampsia is reduced in women who smoke during pregnancy. The objective of this study was to investigate whether smoking affects concentrations of angiogenic factors (sFlt1, PlGF, and sEng) in women at high risk for developing preeclampsia.

Study Design

We performed a secondary analysis of serum samples from 993 high-risk women (chronic hypertension, diabetes, multifetal gestation, and previous preeclampsia) in a preeclampsia prevention trial. sFlt1, sEng and PlGF were measured in serum samples obtained at study entry, which was prior to initiation of aspirin (median 19.0 weeks' [interquartile range of 16.0–22.6 weeks']). Smoking status was determined by self-report.

Results

sFlt1 was not significantly different in smokers from any high-risk groups compared to their nonsmoking counterparts. PlGF was higher among smokers compared to nonsmokers among diabetic women (142.7 [77.4–337.3] vs 95.9 [48.5–180.7] pg/ml, p = 0.005) and women with a history of preeclampsia (252.2 [137.1–486.0] vs 152.2 [73.6–253.7] pg/ml, p = 0.001). sEng was lower in smokers with multifetal gestations (5.8 [4.6–6.5] vs 6.8 [5.5–8.7] ng/ml, p = 0.002) and trended lower among smokers with diabetes (4.9 [3.8–5.6] vs 5.3 [4.3–6.3] ng/ml, p = 0.05). Smoking was not associated with a lower incidence of preeclampsia in any of these groups.

Conclusions

In certain high-risk groups, smoking is associated with changes in the concentrations of these factors towards a pro-angiogenic direction during early pregnancy; however, there was no apparent association between smoking and the development of preeclampsia in our cohort.

Background. Preeclampsia is difficult to diagnose in patients with underlying renal disease and proteinuria. Prior studies show that there is an angiogenic factor imbalance with elevated levels of antiangiogenic proteins soluble fms-like tyrosine kinase 1 (sFlt1) and soluble endoglin (sEng) and reduced levels of the proangiogenic protein, placental growth factor (PlGF) in women with preeclampsia. These angiogenic biomarkers may be useful in distinguishing preeclampsia from other conditions of pregnancy, which may present with overlapping clinical characteristics. Cases. Case 1: A multiparous woman at 18 weeks gestation with nephrotic syndrome presented with hypertensive emergency and worsening renal insufficiency. She underwent induction of labor for severe preeclampsia. Her sFlt1 and sEng levels were at the 97 percentile while her PlGF level was undetectable (less than the 1st percentile). Case 2: A nulliparous woman with lupus nephritis at 22 weeks gestation presented with fetal demise and heart failure. Three weeks previously, the patient had developed thrombocytopenia and hypertensive urgency. She underwent dilation and evacuation. Her angiogenic profile was consistent with severe preeclampsia. Conclusion. Angiogenic factors may provide evidence to support a diagnosis of preeclampsia in patients with preexisting renal disease and proteinuria, conditions in which the classical definition of hypertension and proteinuria cannot be used.

Objective: To test the hypothesis that high circulating concen-trations of maternal anti-angiogenic factors are associated with increased risk of respiratory distress syndrome (RDS). Study Design: This is a nested case-control study of nulliparous women who delivered less than 37 weeks of gestation within the Calcium for Preeclampsia Prevention (CPEP) trial. The study included 116 women with preeclampsia or gestational hyperten-sion and 323 normotensive controls. Soluble fms-like tyrosine kinase 1 (sFlt1), placental growth factor (PlGF) and soluble endo-glin (sEng) in maternal serum were measured at 21–32 weeks of gestation. Results: Preterm infants born to hypertensive mothers were more likely to develop RDS (22.5% vs. 20.9%, p =0.03). After adjustment for gestational age at delivery, the odds ratio for the relationship between hypertension in pregnancy and RDS was 2.18 (95% CI 1.08–4.39). In hypertensive pregnancies women whose infants developed RDS had significantly higher circulating mean sFlt1 levels during midpregnancy (21–32 weeks of gestation) even after adjustment for gestational age at delivery (21,516 pg/mL vs. 7,000 pg/mL, p =0.01). Conclusions: Preterm preeclampsia and gestational hypertension, charac-terized by high circulating levels of sFlt1, are associated with a twofold increased risk of RDS in infants delivered before 37 weeks. Among women with these hypertensive pregnancies circulating sFlt1 concentrations during midpregnancy were substantially higher in women whose infants developed RDS.

Objective

To determine if eclampsia has a different circulating profile of angiogenic [placental growth factor (PlGF)] and anti-angiogenic factors [soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) and soluble endoglin (sEng)] than severe preeclampsia.

Study Design

This cross-sectional study included 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 ELISA.

Results

1) The median concentration of sVEGFR-1 and sEng was higher and of PlGF lower in severe preeclampsia or eclampsia than in normal pregnancy (p<0.001 for all); 2) the median concentrations of these 3 analytes did not differ significantly between the severe preeclampsia and eclampsia groups.

Conclusions

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.

Placental infections with Plasmodium falciparum are associated with fetal growth restriction resulting in low birth weight (LBW). The mechanisms that mediate these effects have yet to be completely described; however, they are likely to involve inflammatory processes and dysregulation of angiogenesis. Soluble endoglin (sEng), a soluble receptor of transforming growth factor (TGF)-β previously associated with preeclampsia in pregnant women and with severe malaria in children, regulates the immune system and influences angiogenesis. We hypothesized that sEng may play a role in development of LBW associated with placental malaria (PM). Plasma levels of sEng were measured in women (i) followed prospectively throughout pregnancy in Cameroon (n = 52), and (ii) in a case-control study at delivery in Malawi (n = 479). The relationships between sEng levels and gravidity, peripheral and placental parasitemia, gestational age, and adverse outcomes of PM including maternal anemia and LBW were determined. In the longitudinal cohort from Cameroon, 28 of 52 women (54%) experienced at least one malaria infection during pregnancy. In Malawi we enrolled two aparasitemic gravidity-matched controls for every case with PM. sEng levels varied over the course of gestation and were significantly higher in early and late gestation as compared to delivery (P<0.006 and P<0.0001, respectively). Circulating sEng levels were higher in primigravidae than multigravidae from both Cameroon and Malawi, irrespective of malarial infection status (p<0.046 and p<0.001, respectively). Peripheral parasitemia in Cameroonian women and PM in Malawian women were each associated with elevated sEng levels following correction for gestational age and gravidity (p = 0.006 and p = 0.033, respectively). Increased sEng was also associated with the delivery of LBW infants in primigravid Malawian women (p = 0.017); the association was with fetal growth restriction (p = 0.003) but not pre-term delivery (p = 0.286). Increased circulating maternal sEng levels are associated with P. falciparum infection in pregnancy and with fetal growth restriction in primigravidae with PM.

OBJECTIVE

Fetal death at the time of diagnosis has higher maternal plasma concentrations of the anti-angiogenic factor, soluble vascular endothelial growth factor receptor (sVEGFR)-1, than that of women with normal pregnancy. An important question is whether these changes are the cause or consequence of fetal death. To address this issue, we conducted a longitudinal nested case-control study and measured the maternal plasma concentrations of selective angiogenic and anti-angiogenic factors before the diagnosis of a fetal death. The anti-angiogenic factors studied included sVEGFR-1, soluble endoglin (sEng), and the angiogenic factor, placental growth factor (PlGF).

Methods

A retrospective longitudinal nested case-control study was conducted. It included 143 singleton pregnancies in the following groups: (1) patients with uncomplicated pregnancies who delivered a term infant with an appropriate weight for gestational age (n=124); and (2) patients who had a fetal death (n=19). Samples were collected at each prenatal visit, scheduled at 4-week intervals from the first trimester until delivery. Plasma concentrations of sVEGFR-1, sEng, and PlGF were determined by specific and sensitive ELISA. A linear mixed-effects model was used for analysis.

Results

1) Linear mixed-effects model analyses indicated that the average profiles of analyte concentrations as a function of gestational age for sVEGFR-1, sEng and PlGF were different between women destined to have a fetal death and those with normal pregnancy outcome after adjusting for covariates (p<0.05); 2) Plasma sVEGFR-1 concentrations in patients destined to have a fetal death were significantly lower between 7 and 11 weeks of gestation and became significantly higher than those of women with a normal pregnancy between 23 and 35 weeks of gestation (p<0.05); 3) Similarly, plasma sEng concentrations of women destined to have a fetal death were lower at 7 weeks of gestation (p=0.04) and became significantly higher than those of women destined to have a normal pregnancy between 23 and 41 weeks of gestation (p<0.05); 4) In contrast, plasma PlGF concentrations were higher among patients destined to develop a fetal death between 7 and 13 weeks of gestation and became significantly lower than those in the control group between 22 and 40 weeks of gestation (p<0.05); 5) The ratio of PlGF/sVEGFR-1 x sEng was significantly higher in women destined to have a fetal death between 7 and 13 weeks of gestation (89%–765%) and significantly lower (45%–76%) than those in normal pregnant women between 20 and 41 weeks of gestation (p<0.05); 6) Similar results were obtained when patients with a fetal death were stratified into those who were diagnosed before or after 37 weeks.

Conclusions

1) Patient destined to have a fetal death, compared to normal pregnancy, was characterized by higher plasma concentrations of PlGF during the first trimester, and this profile changed into an anti-angiogenic one during the second and third trimesters.

Objective

We sought to determine if maternal characteristics are associated with angiogenic profile in the first and second trimester of normotensive pregnancies.

Study Design

Circulating levels of maternal placental like growth factor (PlGF), soluble fms-like tyrosine kinase receptor (sFlt1), and soluble endoglin (sEng) were measured in serum samples collected during the first (median 11.3 weeks) and second trimester (median 17.1 weeks) of 182 normotensive pregnancies. Diastolic blood pressure (DBP), systolic blood pressure (SBP), and mean arterial pressure (MAP) were measured at the same visits when samples were collected to measure angiogenic factors. Linear regression analysis was used to examine associations of the angiogenic measures with maternal characteristics. The association between blood pressure measures and concentrations of angiogenic factors was evaluated using Spearman correlation and linear regression analysis.

Results

In adjusted analyses, nulliparous women had higher sFlt1 concentrations in both first (P=0.06) and second (P=0.001) trimester. Higher BMI was associated with greater sFlt1 concentrations in both the first (P=0.004) and second trimester (P=0.008), but significantly lower sEng concentrations in both trimesters (P=0.002 for first trimester and P=0.0009 for second). Nulliparity and higher BMI also were associated with higher sFlt1/PLGF anti-angiogenic ratios in both first (p=0.05 and p=0.007, respectively) and second trimesters (p=0.003 and p=0.02, respectively). First trimester sFlt1 levels were weakly correlated with first trimester SBP (rs=0.18, p=0.03) and MAP (rs=0.16, p=0.04). Second trimester sEng levels were inversely associated with second trimester MAP (rs= −0.17, p=0.05). Including blood pressure measures in the linear regression models did not change the reported associations of angiogenic factors with maternal characteristics.

Conclusions

These results demonstrate that even early in normotensive pregnancies maternal characteristics are associated with variations in angiogenic profile across this population.

Objective

To describe relations among maternal demographic and lifestyle characteristics and mid-pregnancy levels of angiogenic markers (soluble Fms-like tyrosine kinase-1 (sFlt-1); placental growth factor (PlGF); soluble endoglin (sEng)).

Study Design

In a large pregnancy cohort, linear models were used to evaluate relations among maternal characteristics and mid-pregnancy angiogenic markers with and without covariate adjustment. Associations were examined in a sub-cohort including term and preterm deliveries (N = 1302) and among “normal” term pregnancies (N = 668).

Results

Concentrations of all factors declined with increasing maternal BMI. Multiparous women had lower sFlt-1 levels than primiparas. Higher PlGF and slightly lower sEng were observed among women who smoked at enrollment, but not among those who quit before enrollment. African-American women had higher levels of all markers.

Conclusions

Understanding relations among maternal characteristics and levels of angiogenic factors may improve studies utilizing these markers to examine etiologies and/or to predict adverse pregnancy outcome.

Background

Maternal circulating levels of anti-angiogenic factors such as soluble fms-like tyrosine kinase-1 (sFlt-1), endoglin (sEng) and placental proteins like activin A and inhibin A are increased before the onset of pre-eclampsia. There is evidence for oxidative stress in pre eclampsia. Recently it was shown that placental oxygen concentration is related to sFlt-1 and inhibin A. In addition it is reported that oxidative stress markers are increased in placental tissue delivered after labour. Therefore, the objective of this study is to investigate if these proteins are altered in maternal circulation of labouring pre-eclampsia and normal pregnancies.

Methodology

To assess the effects of labour, samples were taken from 10 normal pregnant (NP) and 10 pre-eclamptic (PE) women pre-labour, full dilation, placental delivery and 24 h. To assess the effects of placental delivery, plasma samples were taken from 10NP and 10PE women undergoing elective Caesarean section, pre-delivery, placental delivery and 10 min, 60 min and 24 h post delivery. SFlt-1 and sEng and activin A and inhibin A were measured using commercial and in house ELISA's respectively.

Results

The levels of sFlt-1 and sEng were significantly higher in PE compared to NP women in both groups. In labour, sFlt-1 levels increased significantly at full dilatation in PE women, before declining by 24 hr. However there was no significant rise in sEng levels in labour. Activin A and inhibin A levels declined rapidly with placental delivery in NP and PE pregnancies. There was a significant rise in activin A levels during labour in PE compared to pre labour, but inhibin levels did not increase.

Conclusion

Labour in pre-eclamptic women increases the levels of sFlt-1 and activin A. This pilot data suggests that increase in the maternal levels of these factors in labour could predict and/or contribute to the maternal syndrome postpartum.

Background

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

Methods

We evaluated the effects of angiotensin II (Ang II) and angiotensin-(1-7) [Ang-(1-7)] on the release of VEGF, PLGF, sFlt1, and sEng from placental chorionic villi (CV). CV were collected from nulliparous third-trimester normotensive and preeclamptic subjects. CV were incubated for 0, 2, 4, and 16 hours with or without Ang II (1 nM and 1 microM) or Ang-(1-7) (1 nM and 1 microM). The release of VEGF, PLGF, sFlt1, sEng, lactate dehydrogenase (LDH), and human placenta lactogen (HPL) was measured by ELISA.

Results

The release of sFlt1, PLGF, sEng from normal and preeclamptic CV increased over time. Release of sFlt1 and sEng was significantly higher from preeclamptic CV. VEGF was below the detectable level of the assay in normal and preeclamptic CV. After 2 hours, sFlt1 release from normal CV was significantly inhibited with Ang II (1 nM and 1 microM) and Ang-(1-7) (1 nM and 1 microM). There was a time-dependent increase in HPL indicating that the CV were functioning normally.

Conclusions

Our study demonstrates a critical inhibitory role of angiotensin peptides on sFlt1 in normal pregnancy. Loss of this regulation in preeclampsia may allow sFlt1 to increase resulting in anti-angiogenesis and end organ damage in the mother.

Background

Severe preeclampsia is associated with increased neutrophil activation and elevated serum soluble endoglin (sEng) and soluble Flt-1 (sFlt-1) in the maternal circulation. To dissect the contribution of systemic inflammation and anti-angiogenic factors in preeclampsia, we investigated the relationships between the circulating markers of neutrophil activation and anti-angiogenic factors in severe preeclampsia or systemic inflammatory state during pregnancy.

Methods and results

Serum sEng, sFlt-1, placenta growth factor, interleukin-6 (IL-6), calprotectin, and plasma α-defensins concentrations were measured by ELISA in 88 women of similar gestational age stratified as: severe preeclampsia (sPE, n = 45), maternal systemic inflammatory response (SIR, n = 16) secondary to chorioamnionitis, pyelonephritis or appendicitis; and normotensive controls (CRL, n = 27). Neutrophil activation occurred in sPE and SIR, as α-defensins and calprotectin concentrations were two-fold higher in both groups compared to CRL (P < 0.05 for each). IL-6 concentrations were highest in SIR (P < 0.001), but were higher in sPE than in CRL (P < 0.01). sFlt-1 (P < 0.001) and sEng (P < 0.001) were ≈20-fold higher in sPE compared to CRL, but were not elevated in SIR. In women with sPE, anti-angiogenic factors were not correlated with markers of neutrophil activation (α-defensins, calprotectin) or inflammation (IL-6).

Conclusions

Increased systemic inflammation in sPE and SIR does not correlate with increased anti-angiogenic factors, which were specifically elevated in sPE indicating that excessive systemic inflammation is unlikely to be the main contributor to severe preeclampsia.

Background

Antihypertensive drugs are believed to lower blood pressure in pre-eclampsia by direct or central vasodilatory mechanisms. However, they could also act by decreasing production of anti-angiogenic proteins involved in the pathophysiology of hypertension and proteinuria in pre-eclampsia (PE). The aim of our study was to evaluate the impact of antihypertensive therapy with alpha methyldopa on maternal circulating levels and placental production of soluble fms-like tyrosine kinase 1 (sFlt-1), soluble endoglin (sEng), vascular endothelial growth factor (VEGF) and placental growth factor (PlGF) in hypertensive disorders of pregnancy.

Methodology/Principal Findings

In a study conducted at University College Hospital and the Homerton University Hospital in London, we recruited 51 women with PE, 29 with gestational hypertension (GH), and 80 matched normotensive controls. Eight (16%) of the women with PE had severe disease. Placental samples were obtained from a further 48 women (14 PE, 10 GH and 24 matched controls). Serum levels of angiogenic factors were measured before and 24–48 hours after commencing antihypertensive therapy with alpha methyldopa for clinical indications. The same parameters were measured in placental extracts. In both PE (P<0.0001) and GH (P<0.05), serum sFlt-1 was increased and PlGF reduced at all gestations (P<0.001) compared to controls. Serum sEng levels were also increased in PE. Placental concentration of sFlt-1 and sEng was significantly higher in women with PE compared to controls and women with GH (P<0.0001). The concentration of PlGF was significantly lower in the placental tissue of women with PE compared to GH (P = 0.008). Antihypertensive treatment was associated with a significant fall in serum and placental content of sFlt1 and sEng in PE only.

Conclusions

Our data suggest that alpha methyldopa may have a specific effect on placental and/or endothelial cell function in pre-eclampsia patients, altering angiogenic proteins.

Background

The purpose of this study was to compare plasma soluble endoglin (sEng) levels with standard clinical evaluation or plasma levels of other angiogenic proteins [soluble fms-like tyrosine kinase 1 (sFlt1) and placental growth factor (PlGF)] in predicting short-term adverse maternal and perinatal outcomes in women with suspected preeclampsia presenting prior to 34 weeks.

Methods and Findings

Data from all women presenting at <34 weeks for evaluation of preeclampsia with singleton pregnancies (July 2009−October 2010) were included in this analysis and sEng levels were measured at presentation. Data was analyzed for 170 triage encounters and presented as median {25−75th centile}. Thirty-three percent of patients (56 of 170) experienced an adverse outcome. sEng levels (ng/ml) were significantly elevated in patients who subsequently experienced adverse outcomes compared to those who did not (32.3 {18.1, 55.8} vs 4.8 {3.2, 8.6}, p<0.0001). At a 10% false positive rate, sEng had higher detection rates of adverse outcomes than the combination of highest systolic blood pressure, proteinuria and abnormal laboratory tests (80.4 {70.0, 90.8} vs 63.8 {51.4, 76.2}, respectively). Subjects in the highest quartile of sEng were more likely to deliver early compared to those in the lowest quartile (HR: 14.96 95% CI: 8.73−25.62, p<0.0001). Natural log transformed sEng correlated positively with log sFlt1 levels (r = 0.87) and inversely with log PlGF levels (r = −0.79) (p<0.0001 for both). Plasma sEng had comparable area under the curve for prediction of adverse outcomes as measurement of sFlt1/PlGF ratio (0.88 {0.81, 0.95} for sEng versus 0.89 {0.83, 0.95} for sFlt1/PlGF ratio, p = 0.74).

Conclusions

In women with suspected preeclampsia presenting prior to 34 weeks of gestation, sEng performs better than standard clinical evaluation in detecting adverse maternal and fetal outcomes occurring within two weeks of presentation. Soluble endoglin was strongly correlated with sFlt1 and PlGF levels, suggesting common pathogenic pathways leading to preeclampsia.

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. Non-parametric 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.

Objective

To determine if the histology of placental abruption differs by maternal thrombophilia status.

Study design

This was a multicenter, case-control study of women with abruption and delivering at ≥20 weeks’ gestation, collected as part of the ongoing New Jersey-Placental Abruption Study. Women were identified by clinical criteria of abruption. Maternal blood was collected postpartum and tested for anticardiolipin antibodies, and mutations in the Factor V Leiden and prothrombin genes. Cases were comprised of women with an abruption and a positive thrombophilia screen. Controls were comprised of women with an abruption and a negative thrombophilia screen. All placental histology was systematically reviewed by two perinatal pathologists, blinded to the abruption status.

Results

A total of 135 women with placental abruption were identified, of which 63.0% (n=85) had at least one diagnosed maternal thrombophilia. There were increases in the rates of meconium-stained membranes (7.9% versus 2.1%, P=0.015) and decidual necrosis (4.5% versus 2.1%, P=0.023) when a maternal thrombophilia was diagnosed. Although there was no difference in the overall presence of infarcts between the 2 groups (27.0% versus 38.3%, P=0.064), the presence of an old infarct was more common among women with a positive thrombophilia screen (83.3% versus 44.4%, P=0.003).

Conclusion

Placental abruption with a positive maternal thrombophilia screen is associated with higher rates of old placental infarcts and decidual necrosis compared with abruption when thrombophilia is not diagnosed. These lesions suggest a chronic etiology of placental abruption in the presence of a maternal thrombophilia.

Progressive left ventricular (LV) dysfunction induces expression of the cytokine transforming growth factor-beta (TGFb1). Endoglin (CD105) is a TGFb1 co-receptor that is released into the circulation as soluble endoglin (sEng). The objective of this study was to assess serum levels of sEng in heart failure and to identify the predictive value of sEng for detecting elevated left ventricular end-diastolic pressures (LVEDP). We measured sEng levels in 82 consecutive patients with suspected LV dysfunction referred for determination of left heart filling pressures by cardiac catheterization. Among these subjects sEng levels correlated with LVEDP (R=0.689; p<0.0001) irrespective of LV ejection fraction (LVEF). Using a receiving operative characteristic (ROC) curve, sEng levels predicted an LVEDP≥16mmHg with an area-under-the-curve (AUC) of 0.85, exceeding measured AUCs for both atrial- and brain-natriuretic peptide, currently used biomarkers for heart failure diagnosis (ANP:0.68; BNP:0.65, p<0.01 vs sEng respectively). In 10 subjects receiving medical therapy for heart failure guided by invasive hemodynamic monitoring, decreased pulmonary capillary wedge pressure was associated with a reduced sEng level (R=0.75, p=0.008). Finally, compared to 25 healthy controls, sEng levels were elevated in subjects with suspected LV dysfunction (3589±588 vs 4257±966 pg/mL, respectively, p<0.005) and correlated directly with New York Heart Association class (NYHA; R=0.501, p<0.001). In conclusion, circulating levels of sEng are elevated in patients with increased LVEDP and NYHA class, irrespective of LVEF. Soluble endoglin levels also decrease in association with reduced cardiac filling pressure after diuresis. These findings identify circulating sEng as a sensitive measure of elevated left heart filling pressure.

Miscarriage is the most common complication of pregnancy. Pre-clinical miscarriage has an estimated incidence of 30%, whilst clinical miscarriage has an incidence of 12-15%. Two thirds of pregnancies lost to miscarriage are believed to be attributable to defective placentation, thus a number of studies have sought to identify markers of defective placentation that could be used as clinical biomarkers of miscarriage. Decreased soluble FMS-like tyrosine kinase-1 (sFlt1), placental growth factor (PlGF), and soluble endoglin (sEng) in the maternal circulation during the first trimester have recently been proposed as potential markers of pregnancy loss. However, in these studies clinical samples were only obtained once women had presented with symptoms of miscarriage. In this study we prospectively screened serum samples collected from asymptomatic women with a viable fetus. We assessed maternal serum levels of sFlt1, PlGF and sEng across the first trimester of normal pregnancy and compared levels between women who continued to a live birth, to those who subsequently miscarried. Both sFlt1 and PlGF significantly (p≤0.05) increased across gestation in normal pregnancy with serum levels rising from 0.65±0.12 ng/ml at 6 weeks to 1.85±0.24 ng/ml at 12 weeks for sFlt1, and 57.2±19.2 pg/ml to 106±22.7 pg/ml for PlGF. sEng remained unchanged throughout the the first trimester. Importantly we detected a significant (35%, p≤0.05) decrease in sFlt1 levels between our control and miscarriage cohort, however there was significant overlap between cases and controls, suggesting serum sFlt1 is unlikely to be useful as a clinical biomarker in asymptomatic women. Nevertheless, our data suggests a dysregulation of angiogenic factors may be involved in the pathophysiology of miscarriage.

Objective

To determine if maternal plasma concentrations of placental growth factor (PlGF), soluble endoglin (sEng), soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) and -2 could identify patients at risk for developing preeclampsia (PE) requiring preterm delivery.

Study design

Patients presenting with the diagnosis ‘rule out PE’ to the obstetrical triage area of our hospital at <37 weeks of gestation (n=87) were included in this study. Delivery outcomes were used to classify patients into 4 groups: I) patients without PE or those with gestational hypertension (GHTN) or chronic hypertension (CHTN) who subsequently developed PE at term (n=19); II): mild PE who delivered at term (n=15); III): mild disease (mild PE, GHTN, CHTN) who subsequently developed severe PE requiring preterm delivery (n=26); and IV): diagnosis of severe PE (n=27). Plasma concentrations of PlGF, sEng, sVEGFR-1 and -2 were determined at the time of presentation by ELISA. Reference ranges for analytes were constructed by quantile regression in our laboratory (n=180; 1,046 samples). Comparisons among groups were performed using multiples of the median (MoM) and parametric statistics after log transformation. Receiver operating characteristic curves, logistic regression and survival analysis were employed for analysis.

Results

The mean MoM plasma concentration of PlGF/sVEGFR-1, PlGF/sEng, PlGF, sVEGFR-1 and -2, and sEng in Group III was significantly different from Group II (all p<0.05). A plasma concentration of PlGF/sVEGFR-1 ≤ 0.05 MoM or PlGF/sEng ≤ 0.07 MoM had the highest likelihood ratio of a positive test (8.3, 95% CI 2.8–25 and 8.6, 95% CI 2.9–25, respectively), while that of PlGF ≤0.396 MoM had the lowest likelihood ratio of a negative test (0.08, 95% CI 0.03–0.25). The association between low plasma concentrations of PlGF/sVEGFR-1 (≤0.05 MoM) as well as that of PlGF/sEng (≤ 0.07 MoM) and the development of severe PE remained significant after adjusting for gestational age at presentation, average systolic and diastolic blood pressure, and a history of chronic hypertension [adjusted odds ratio (OR) = 27 (95% CI 6.4–109) and adjusted OR 30 (95% CI 6.9–126), respectively]. Among patients who presented <34 weeks gestation (n=59), a plasma concentration of PlGF/sVEGFR-1 <0.033 MoM identified patients who delivered within 2 weeks because of PE with a sensitivity of 93% (25/27) and a specificity of 78% (25/32). This cut-off was associated with a shorter interval-to-delivery due to PE [hazard ratio = 6 (95% CI 2.5–14.6)].

Conclusions

Plasma concentrations of angiogenic/anti-angiogenic factors are of prognostic value in the obstetrical triage area. These observations support the value of these biomarkers in the clinical setting for the identification of the patient at risk for disease progression requiring preterm delivery.

Objective

Angiogenic factors have been implicated in the pathophysiology of sepsis. In experimental models of sepsis (endotoxemia and/or cecal ligation puncture), there is increased expression of vascular endothelial growth factors (VEGF) and the administration of exogenous soluble VEGF receptor (sVEGFR)-1, an antagonist to VEGF, reduces morbidity and mortality. Moreover, a dramatic elevation in sVEGFR-1 has been demonstrated in human sepsis. Although a balance between angiogenic and anti-angiogenic factors is essential for feto-placental development, the changes of angiogenic factors during pregnancy in the context of infection have never been explored. Angiogenic factors also play crucial roles in the pathophysiology of preeclampsia. This study was conducted to determine if maternal plasma concentrations of placental growth factor (PlGF), sVEGFR-2 and soluble endoglin (sEng) change in pregnancies complicated by acute pyelonephritis (AP) compared to normal pregnancy and preeclampsia (PE).

Study Design

A case-control study was conducted in patients with AP, normal pregnant women (NP) and patients with PE (n=36 for each group) matched for gestational age. AP was diagnosed in the presence of fever (temperature ≥ 38°C), clinical signs of infection, and a positive urine culture for micro-organisms. Plasma concentrations of PlGF, sVEGFR-2 and sEng were determined by ELISA. The results of plasma sVEGFR-1 concentrations has previously been reported before, but were included in this study to provide a complete picture of the angiogenic/anti-angiogenic profiles. Serum concentrations of interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12p70, IL-13, interferon (IFN)-γ, Granulocyte macrophage colony stimulating factor (GM-CSF), and tumor necrosis factor (TNF)-α were also determined using high sensitivity multiplexed immunoassays in patients with AP and NP.

Results

AP was associated with a lower median plasma concentration of PlGF and sVEGFR-2 than NP (both p<0.001). There were no significant differences in the median plasma concentrations of sEng and sVEGFR-1 between AP and NP (p=0.7 and 0.5 respectively). In contrast, there was a 5-fold decrease of the median plasma concentration of PlGF, and an 8-10 fold increase of the median plasma concentrations of sVEGFR-1 and sEng in PE compared to those in AP (all p<0.001). No significant difference in the median plasma concentration of sVEGFR-2 was observed between patients with PE and AP (p=0.5). Pregnant women with acute pyelonephritis had median plasma concentrations of IL-6, IL-7, IL-8, IL-10, IFN-γ, and TNF-α significantly higher than those in normal pregnant women (all p<0.001, except IL-7 p=0.004).

Conclusion

AP is associated with changes in the profile of angiogenic and anti-angiogenic factors. Although some of these changes resemble those in PE (decreased PlGF and sVEGFR-2), the magnitude of the changes of PlGF is much higher in PE. We conclude that despite high plasma inflammatory cytokine concentrations, acute systemic inflammation in pregnancy has a different angiogenic/anti-angiogenic profile than that of preeclampsia.

Background

Preeclampsia (PE) is a prevalent life-threatening hypertensive disorder of pregnancy. The circulating antiangiogenic factor, soluble endoglin (sEng), is elevated in the blood circulation of women with PE and contributes to disease pathology. However, the underlying mechanisms responsible for its induction in PE are unknown.

Methods and Results

Here we discovered that a circulating autoantibody, the angiotensin receptor agonistic autoantibody (AT1-AA), stimulates sang production via AT1 angiogenesis receptor activation in pregnant mice but not non-pregnant mice. Subsequently we demonstrate that the placenta is a major source contributing to sang induction in vivo and AT1-AA injected pregnant mice display the impaired placental angiogenesis. Using drug screening, we identified TNF-α as a circulating factor increased in the serum of autoantibody-injected pregnant mice contributing to AT1-AA-mediated sang induction in human umbilical vascular endothelial cells (HUVECs). Subsequently, among all the drugs screened we found that hemin, an inducer of heme oxygenase-1 (HO-1), functions as a break to control AT1-AA mediated sang induction by suppressing TNF-α signaling in Havocs. Finally, we demonstrated that AT1-AA-mediated decreased angiogenesis seen in human placenta villous explants was attenuated by TNF-α neutralizing antibodies, soluble TNF-α receptors and hemi, an inducer of home oxygenase, by abolishing both sang and sFlt-1 induction.

Conclusions

Our findings demonstrate that AT1-AA-mediated TNF-α induction, by overcoming its negative regulator, HO-1, is a key underlying mechanism responsible for impaired placenta angiogenesis by inducing both sEng and sFlt-1 secretion from human villous explants and provide important new targets for diagnosis and therapeutic intervention in the management of PE.

Objective

Angiogenesis is critical for successful pregnancy. An anti-angiogenic state has been implicated in preeclampsia, fetal growth restriction and fetal death. Increased maternal plasma concentrations of the anti-angiogenic factor, soluble vascular endothelial growth factor receptor (sVEGFR)-1, have been reported in women with preeclampsia and in those with fetal death. Recent observations indicate that an excess of sVEGFR-1 and soluble endoglin (sEng) is also present in the amniotic fluid of patients with preeclampsia. The aim of this study was to determine if fetal death is associated with changes in amniotic fluid concentrations of sVEGFR-1 and sEng, two powerful anti-angiogenic factors.

Study Design

This cross-sectional study included patients with fetal death (n=35) and controls (n=129). Fetal death was subdivided according to clinical circumstances into: 1) unexplained (n=25); 2) preeclampsia and/or placental abruption (n=5); and 3) chromosomal/congenital anomalies (n=5). The control group consisted of patients with preterm labor (PTL) who delivered at term (n=92) and women at term not in labor (n=37). AF concentrations of sVEGFR-1 and sEng were determined by ELISA. Non-parametric statistics and logistic regression analysis were applied.

Results

1) Patients with a fetal death had higher median amniotic fluid concentrations of sVEGFR-1 and sEng than women in the control group (p<0.001 for each); 2) these results remained significant among different subgroups of stillbirth (p<0.05 for each); and 3) amniotic fluid concentrations of sVEGFR-1 and those of sEng above the 3rd quartile were associated with a significant risk of unexplained preterm fetal death (adjusted OR = 10.8; 95%CI 1.3-89.2 and adjusted OR 87; 95% CI 2.3-3,323, respectively).

Conclusion

Patients with an unexplained fetal death at diagnosis are characterized by an increase in the amniotic fluid concentrations of sVEGFR-1 and sEng. These observations indicate that an excess of anti-angiogenic factors in the amniotic cavity is associated with unexplained fetal death especially in preterm gestations.