Higher sFlt-1 Research Articles

O11. Evaluation of the endocannabinoid system in preeclampsia

Introduction The endocannabinoid system plays a key role in female reproduction, including implantation, decidualization and placentation. A growing number of studies indicate that placental and peripheral blood anandamide levels correlate closely with both spontaneous miscarriage and ectopic pregnancy. Anandamide has also been implicated in blood pressure regulation. Objectives In this study, we aimed to analyze placental expression and localization of cannabinoid receptor 1 (CB1), CB2 and fatty acid amid hydrolase (FAAH), as well as circulating anandamide levels in normal pregnancy and preeclampsia. Methods We determined CB1, CB2 and FAAH expressions by Western blotting and immunohistochemistry in placental samples collected directly after Cesarean section in 18 preeclamptic patients and 18 normotensive, healthy pregnant women. Serum anandamide concentrations were measured by high performance liquid chromatography–mass spectrometry (HPLC–MS) technique in 43 preeclamptic patients and 71 healthy pregnant women. Serum total soluble fms-like tyrosine kinase-1 (sFlt-1) and biologically active placental growth factor (PlGF) levels were assessed by electrochemiluminescence immunoassay. Results CB1 expression semi-quantified by Western blotting was significantly higher in preeclamptic placenta, and these findings were confirmed by immunohistochemistry. CB1 immunoreactivity was markedly stronger in syncytiotrophoblasts, the mesenchymal core, decidua, villous capillary endothelial and smooth muscle cells, as well as in the amnion in preeclamptic samples compared to normal pregnancies. However, we did not find significant differences between preeclamptic and normal placenta in terms of CB2 and FAAH expressions and immunoreactivity. Serum levels of anandamide were significantly lower in preeclamptic patients than in healthy pregnant women. Preeclamptic patients had significantly higher sFlt-1 levels and significantly lower PlGF concentrations as compared to healthy pregnant women. Serum anandamide concentrations did not correlate with serum levels of sFlt-1 and PlGF in our healthy pregnant and preeclamptic groups. Conclusion We observed markedly higher expression of CB1 protein in preeclamptic placental tissue. Increased CB1 expression might cause abnormal decidualization and impair trophoblast invasion, thus being involved in the pathogenesis of preeclampsia. Nevertheless, we did not find significant differences between preeclamptic and normal placental tissue regarding CB2 and FAAH expressions. Furthermore, serum anandamide concentrations were decreased in women with preeclampsia. While the detailed pathogenesis of preeclampsia is still unclear, the endocannabinoid system could play a role in the development of the disease.

Circulating Angiogenic Factors and the Risk of Preeclampsia in Systemic Lupus Erythematosus Pregnancies.

To investigate whether angiogenic factors are associated with risk of developing preeclampsia in pregnant women with systemic lupus erythematosus (SLE). We performed a nested case-control study within a cohort of SLE women with singleton pregnancies. The study included 42 patients with SLE who eventually developed preeclampsia and 75 normal SLE pregnancies. Serum samples were collected at 4-week intervals (from weeks 12 to 36). Serum samples were analyzed for soluble fms-like tyrosine kinase-1 (sFlt-1), placental growth factor (PlGF), and soluble endoglin (sEng). Women destined to develop preeclampsia had lower PlGF levels and higher sFlt-1 and sEng levels, and a higher sFlt-1/PlGF ratio than normal pregnancies. These changes became significant at 12 weeks in patients destined to develop either early onset (< 34 weeks, p ≤ 0.003) or late-onset preeclampsia (≥ 34 weeks, p ≤ 0.02). The risk to develop preeclampsia was higher among patients with PlGF concentration values in the lowest quartile or with sFlt-1 and sEng levels, and sFlt-1/PlGF ratio, in the highest quartile of the normal SLE pregnancies distribution. The OR were higher and appeared earlier in patients destined to develop early onset preeclampsia (OR ≥ 16.2, from Week 12 onward) than in patients who presented preeclampsia later (OR ≥ 8.9, from Week 24 onward). Changes in circulating concentrations of sFlt-1, PlGF, sEng, and the sFlt-1/PlGF ratio precede the onset of preeclampsia in SLE pregnancies. The risk profile of circulating angiogenic factors for developing preeclampsia distinctly evolves depending on whether this condition is manifested earlier or later.

Soluble Flt-1 links microvascular disease with heart failure in CKD.

Chronic kidney disease (CKD) is associated with an increased risk of heart failure (HF). Elevated plasma concentrations of soluble Flt-1 (sFlt-1) have been linked to cardiovascular disease in CKD patients, but whether sFlt-1 contributes to HF in CKD is still unknown. To provide evidence that concludes a pathophysiological role of sFlt-1 in CKD-associated HF, we measured plasma sFlt-1 concentrations in 586 patients with angiographically documented coronary artery disease and renal function classified according to estimated glomerular filtration rate (eGFR). sFlt-1 concentrations correlated negatively with eGFR and were associated with signs of heart failure, based on New York Heart Association functional class and reduced left ventricular ejection fraction (LVEF), and early mortality. Additionally, rats treated with recombinant sFlt-1 showed a 15 % reduction in LVEF and a 29 % reduction in cardiac output compared with control rats. High sFlt-1 concentrations were associated with a 15 % reduction in heart capillary density (number of vessels/cardiomyocyte) and a 24 % reduction in myocardial blood volume. Electron microscopy and histological analysis revealed mitochondrial damage and interstitial fibrosis in the hearts of sFlt-1-treated, but not control rats. In 5/6-nephrectomised rats, an animal model of CKD, sFlt-1 antagonism with recombinant VEGF121 preserved heart microvasculature and significantly improved heart function. Overall, these findings suggest that a component of cardiovascular risk in CKD patients could be directly attributed to sFlt-1. Assessment of patients with CKD confirmed that sFlt-1 concentrations were inversely correlated with renal function, while studies in rats suggested that sFlt-1 may link microvascular disease with HF in CKD.

PP36 - Hydrogen sulphide rescues preeclampsia-like phenotype aggravated by high sFlt-1 in placenta growth factor (PlGF) deficiency

Placenta growth factor (PlGF) deficient mice are fertile at a Mendelian ratio. Interestingly, low maternal plasma levels of PlGF are strongly associated with early onset of preeclampsia, a pregnancy hypertensive disorder characterised by high blood pressure, proteinuria and fetal growth restriction. PlGF is increasingly being recognised as an early diagnostic biomarker, but the physiological importance of PlGF in the pathogenesis of preeclampsia is unknown. We investigated whether the decreased levels of PlGF in pregnancy exacerbate the fetal growth restriction associated with preeclampsia in the presence of high sFlt-1 and the potential of hydrogen sulphide to ameliorate these effects. Pregnant PlGF−/− mice were injected with adenovirus encoding sFlt-1 (Ad-sFlt-1) at 1 × 109 pfu/ml at E10.5 and mean arterial blood pressure (MAP), biochemical and histological analysis of maternal kidney, placenta and embryos were assessed at the end of pregnancy. Ad-sFlt-1 significantly increased MAP and induced severe glomerular endotheliosis in PlGF−/− mice compared to wild-type animals. Soluble Flt-1 also significantly elevated albumin–creatinine ratio and increased levels of urinary kidney injury molecule-1, a marker for proximal tubule injury. Furthermore, sFlt-1 over expression increased fetal resorption rate in the PlGF−/− mice and promoted abnormal placental vascularisation. To determine whether placental PlGF is critical for preventing fetal growth restriction associated with preeclampsia, we generated haploinsufficient PlGF+/− placentas and embryos in dams and exposed to high sFlt-1 environment. These mothers showed reduced fetal resorption, gestational hypertension and proteinuria when compared to pregnant PlGF−/− mice. Furthermore, treatment with hydrogen sulphide-releasing agent, GYY4137, significantly reduced resorption, hypertension and proteinuria observed in Ad-sFlt-1 treated pregnant PlGF−/− mice. Our study shows that placental PlGF is a critical protective factor against the damaging effects of high sFlt-1 associated with preeclampsia and activation of the hydrogen sulphide pathway may rescue preeclampsia phenotypes even under low PlGF environment.

OP14 - Preeclampsia: An accelerator–brake defect disorder

Life's perfect partnership starts with the placenta. If we get this right, we have the best chance of healthy life. In preeclampsia, we have a failing placenta. Preeclampsia kills one pregnant woman every minute and the life expectancy of those who survive is greatly reduced. Preeclampsia is treated roughly the same way it was when Thomas Edison was making the first silent movie. Globally, millions of women risk death to give birth each year and almost 300,000 lose their lives in this process. Over half a million babies around the world die each year as a consequence of preeclampsia. Despite decades of research, we lack pharmacological agents to treat it. Maternal endothelial dysfunction is a central phenomenon responsible for the clinical signs of preeclampsia. In the late nineties, we discovered that vascular endothelial growth factor (VEGF) stimulated nitric oxide release. This led us to suggest that preeclampsia arises due to the loss of VEGF activity, possibly due to a rise in soluble Flt-1 (sFlt-1), the natural antagonist of VEGF. Researchers have shown that high sFlt-1 elicits preeclampsia-like signs in pregnant rats and sFlt-1 increases before the clinical signs of preeclampsia in pregnant women. We demonstrated that removing or reducing this culprit protein from preeclamptic placenta restored the angiogenic balance. Heme oxygenase-1 (HO-1 or Hmox1) that generates carbon monoxide (CO), biliverdin (rapidly converted to bilirubin) and iron is cytoprotective. We showed that the Hmox1/CO pathway prevents human placental injury caused by pro-inflammatory cytokines and suppresses sFlt-1 and soluble endoglin release, factors responsible for preeclampsia phenotypes. The other key enzyme we identified is the hydrogen sulfide generating cystathionine-gamma-lyase (CSE or Cth). These are the only two enzyme systems shown to suppress sFlt-1 and to act as protective pathways against preeclampsia phenotypes in animal models. We also showed that when hydrogen sulfide restores placental vasculature, it also improves lagging fetal growth. These molecules act as the inhibitor systems in pregnancy and when they fail, this triggers preeclampsia. Discovering that statins induce these enzymes led us to an RCT to develop a low-cost therapy (StAmP Trial) to prevent or treat preeclampsia. If you think of pregnancy as a car then preeclampsia is an accelerator–brake defect disorder. Inflammation, oxidative stress and an imbalance in the angiogenic milieu fuel the ‘accelerator’. It is the failure in the braking systems (the endogenous protective pathway) that results in the ‘accelerator’ going out of control until the system crashes, manifesting itself as preeclampsia.

Early pregnancy maternal and fetal angiogenic factors and fetal and childhood growth: the Generation R Study.

What are the effects of maternal and fetal soluble fms-like tyrosine kinase 1 (sFlt-1) and placental growth factor (PlGF) concentrations on fetal and childhood growth patterns? An angiogenic profile that is characterized by both low early pregnancy maternal sFlt-1 and PlGF concentrations and higher sFlt-1 concentrations, lower PlGF concentrations or a higher sFlt-1:PlGF ratio in umbilical cord blood is associated with a reduced fetal and childhood growth. An imbalance in maternal and fetal sFlt-1 and PlGF concentrations has been suggested to affect pregnancy outcomes. However, their effects on longitudinal fetal and childhood growth remain largely unknown. This study was performed in 5980 mothers and 4108 of their children, participating in the Generation R Study; a population-based prospective cohort study from fetal life onwards in Rotterdam, the Netherlands (2001-2005). Blood samples were obtained from mothers in early and mid-pregnancy and from the umbilical vein at delivery. Fetal and childhood growth characteristics (weight and length) were measured repeatedly by ultrasound and physical examinations until the age of 6 years. We assessed the associations of maternal and fetal angiogenic factors with fetal and childhood growth using repeated measurement regression models. Logistic regression models were used to determine associations between angiogenic factors and small for gestational age at birth (SGA). Compared with early pregnancy maternal sFlt-1 concentrations in the lowest quintile, early pregnancy maternal sFlt-1 concentrations in the highest quintile were associated with a higher fetal weight growth resulting in a higher birthweight (difference in birthweight 0.33 standard deviation score (SDS); 95% Confidence Interval (CI) 0.25-0.41), a lower risk of SGA (Odds Ratio (OR) 0.36; 95% CI 0.27-0.48) and a subsequent higher weight growth until the age of 6 years. Early pregnancy maternal PlGF concentrations in the lowest quintile were associated with a reduced weight growth pattern resulting in a smaller birthweight (difference in birthweight -0.34 SDS; 95% CI -0.44, -0.25), an increased risk of SGA (OR 3.48; 95% CI 2.39-5.08) and a lower weight growth throughout childhood. An early pregnancy maternal sFlt-1:PlGF ratio in the highest quintile was associated with a higher fetal weight growth pattern from 30 weeks onwards, resulting in a higher weight at birth (difference in birthweight 0.09 SDS; P-value <0.05), which remained present until the age of 2 years. Newborns with higher umbilical cord sFlt-1 concentrations, lower PlGF concentrations or a higher sFlt-1:PlGF ratio showed a lower fetal and childhood weight growth from 30 weeks gestation onwards until the age of 6 years (P-value <0.05). Similar patterns were observed in relation to fetal and childhood length growth. The study is an observational study. Therefore, no causal relationships can be established. Both a maternal and fetal angiogenic imbalance may affect fetal and childhood growth. Changes in angiogenic profiles may be involved in the pathways linking fetal growth restriction with the long-term risk of vascular disease in adulthood. The first phase of the Generation R Study is made possible by financial support from The Erasmus Medical Centre, Rotterdam, the Erasmus University Rotterdam, and the Netherlands Organization for Health Research and Development (ZonMw 21000074). V.W.V.J. received additional grants from the Netherlands Organization for Health Research and Development (ZonMw VIDI). M.I.B.-B. is financially supported by the Bo Hjelt foundation (grant 2009). The authors have no competing interests.

Predictive value of angiogenic factors, clinical risk factors and uterine artery Doppler for pre-eclampsia and fetal growth restriction in second and third trimester pregnancies in an Ecuadorian population

Objective: To evaluate the performance of angiogenic factors, maternal risks and uterine artery Doppler (UAD) in the prediction of pre-eclampsia (PE) and fetal growth restriction (FGR) in a high-risk Ecuadorian population. Methods: Patients with singleton pregnancies (n = 346) were investigated at two clinical visits (18–25 weeks and 28–32 weeks). Mean uterine artery (UA), pulsatility index (PI) and maternal biomarkers (soluble fms-like tyrosine kinase-1, placental growth factor, sFlt-1/PLGF ratio) were obtained. The main endpoints were PE and FGR. UA PI and angiogenic factor levels were compared for the groups with PE (n = 34), FGR (n = 26), PE & FGR (n = 14) and controls (n = 272). Multivariable stepwise logistic regression was used to construct prediction models. Results: Pregnancies with either FGR or PE & FGR exhibited in the second trimester a significantly higher mean UA PI and sFlt-1/PLGF ratio and lower PLGF values compared to controls. In the third trimester, all groups with adverse outcome demonstrated significantly lower PLGF levels and a higher sFlt-1/PLGF ratio compared to normal pregnancies. Differences were most pronounced for pregnancies that developed PE and FGR for both time intervals. The combination of UAD and sFlt-1/PLGF ratio improved the predictive capacity for PE and FGR compared to each parameter alone. The best performance was obtained by integrating anamnestic risk factors, resulting in an area under the receiver operating curve for PE of 0.85 and 0.89 and for FGR of 0.79 and 0.77 in the second and third trimester, respectively. Conclusion: In a high-altitude Ecuadorian population, angiogenic factors and UA PI were useful tools in the prediction of PE and/or FGR. The highest performance was achieved by the combination of these factors, including obstetric and medical history.

Short call abstracts.

Short call abstracts.

An endogenous retrovirus involved in placental morphogenesis in Bovinae: diversity of mammalian placentas and endogenous retroviruses

An endogenous retrovirus involved in placental morphogenesis in Bovinae: diversity of mammalian placentas and endogenous retroviruses

Altered Hemodynamics and Hyperuricemia Accompany an Elevated sFlt-1/PlGF Ratio Before the Onset of Early Severe Preeclampsia

ObjectivesEarly identification of women at risk of developing early-onset severe preeclampsia (sPE) is a key objective in obstetrics. An elevated ratio of serum soluble fms-like tyrosine kinase (sFlt-1) to placenta-like growth factor (PlGF) (sFlt-1/PlGF ratio) precedes overt hypertension. The longitudinal relationship between this biomarker, maternal hemodynamics, and maternal serum uric acid during the pre-clinical phase is unknown. Study DesignWe followed 20 normotensive women at high risk of developing sPE from 20 weeks until delivery or 34 weeks’ gestation. Non-invasive hemodynamic monitoring using bioreactance technology was performed at 20 to 22, 24 to 26, 28 to 30, and 32 to 34 weeks’ gestation. Serum uric acid, sFlt-1, and PlGF were measured simultaneously. ResultsSix of 20 women (30%) delivered before 33 weeks with sPE and had significantly higher mean total peripheral resistance (TPR), higher serum uric acid, and higher sFlt-1/PlGF ratios at 24 weeks’ gestation than unaffected individuals. The area under the curve, cut-off values, and sensitivity and specificity to predict sPE at 24 weeks were as follows: TPR 0.84, 1250 dyne.s.cm-5, 80%, 93%; sFlt-1/PlGF ratio 0.94, 55, 100%, 93%; and serum uric acid 0.99, 255 μmol/L, 100%, 93%. TPR and sFlt-1 were positively correlated in the sPE group before antihypertensive treatment (r=0.65, P=0.01). Serum uric acid correlated with both sFlt-1 (r=0.65, P=0.003) and sFlt-1/PlGF ratio (r=0.54, P=0.02). ConclusionA combination of non-invasive determination of TPR together with measurement of serum uric acid may identify a subset of clinically high-risk women with evolving sPE, independent of the determination of the sFlt-1/PlGF ratio. The predictive ability of this integrated approach needs to be assessed in a larger cohort of women to further confirm its utility.

A trio of risk factors for the onset of preeclampsia in the second and early third trimesters.

We evaluated the biological interaction among mean blood pressure (MBP), uterine artery Doppler (UAD), and the soluble fms-like tyrosine kinase 1 (sFlt-1)/placental growth factor (PlGF) ratio for preeclampsia (PE) risk. A prospective cohort study. In 1239 pregnant women, MBP and UAD were measured at 16-23weeks of gestation, and plasma levels of the sFlt-1/PlGF ratio at 19-25weeks and 26-31weeks. A Cox proportional hazard model was used. Women with a low sFlt-1/PlGF ratio and either low BP or normal UAD were set as controls. The relative excess risk due to biological interaction (RERI) was calculated using the following equation: RERI=hazard ratio (HR) in women with high sFlt-1/PlGF and both high BP and abnormal UAD (group 3) - HR in women with both high BP and abnormal UAD alone (group 1) - HR in women with high sFlt-1/PlGF alone (group 2)+1. RERI⩾10 was considered to be strong. At 19-25weeks, the HR and 95% confidence intervals (CI) in group 1, group 2, and group 3 were 7.4 (3.1-17.4), 15.3 (4.5-52.2), and 107.0 (41.0-279), respectively, and the RERI for PE was 85.3. At 26-31weeks, the HR and 95% CI in each group were 8.3 (2.9-23.2), 7.5 (0.97-57.8), and 69.0 (18.5-256), respectively; the RERI for PE was 54.2. We found a trio of risk factors for the onset of PE in the second and early third trimesters: high BP, abnormal UAD, and high sFlt-1/PlGF ratio.

2-Methoxyestradiol deficiency is strongly related to hypertension in early onset severe pre-eclampsia

2-Methoxyestradiol (2ME) deficiency leading to placental insufficiency has been related to pre-eclampsia (PE). Here we investigate whether 2ME is related to clinical profiles and vasoactive factors in early onset severe PE patients. 28 severe PE patients and 20 uncomplicated normal pregnant women, with gestational weeks between 24 and 32weeks, were recruited. All cases and controls had singleton pregnancies and were matched for maternal age, parity, body mass index, and gestational weeks. Plasma levels of 2ME, estradiol (E2), soluble Fms-like tyrosine kinase-1 (sFLT-1), endothelin-1 (ET-1), nitric oxide (NO) were determined. PE patients had significant lower 2ME [906(422-1768) vs. 2032(1400-2910)pg/mL, P=0.002], higher sFLT-1 [5.55(3.24-11.22) vs. 3.13(2.17-5.36)ng/mL, P=0.015] and higher NO [122.40(72.92-168.23) vs. 45.83(25.52-61.46)μmol/L, P=0.0008] levels in their plasma than the controls. In the PE group, plasma 2ME level correlated negatively with systolic pressure (r=-0.48, P=0.012), diastolic pressure (r=-0.52, P=0.007) and mean arterial pressure (r=-0.54, P=0.005) even after controlling for maternal age; 2ME level did not correlate with proteinuria, plasma levels of E2, sFLT-1, ET-1 or NO. In the control group, plasma 2ME level did not correlate with any of the above clinical profiles or laboratory measurements. 2ME levels were markedly lower in early onset severe PE and they correlated inversely with blood pressure only in women with PE. Although we cannot tell whether lower 2ME level is the causation or the result of PE, our study provides clinical evidences that 2ME deficiency is strongly related to hypertension in early onset severe PE patients.

The Role of Angiogenic and Antiangiogenic Factors in the Second Trimester in the Prediction of Preeclampsia in Pregnant Women With Type 1 Diabetes

OBJECTIVETo assess the association between circulating angiogenic and antiangiogenic factors in the second trimester and risk of preeclampsia in women with type 1 diabetes.RESEARCH DESIGN AND METHODSMaternal plasma concentrations of placental growth factor (PlGF), soluble fms-like tyrosine kinase 1 (sFlt-1), and soluble endoglin (sEng) were available at 26 weeks of gestation in 540 women with type 1 diabetes enrolled in the Diabetes and Preeclampsia Intervention Trial.RESULTSPreeclampsia developed in 17% of pregnancies (n = 94). At 26 weeks of gestation, women in whom preeclampsia developed later had significantly lower PlGF (median [interquartile range]: 231 pg/mL [120–423] vs. 365 pg/mL [237–582]; P < 0.001), higher sFlt-1 (1,522 pg/mL [1,108–3,393] vs. 1,193 pg/mL [844–1,630] P < 0.001), and higher sEng (6.2 ng/mL [4.9–7.9] vs. 5.1 ng/mL[(4.3–6.2]; P < 0.001) compared with women who did not have preeclampsia. In addition, the ratio of PlGF to sEng was significantly lower (40 [17–71] vs. 71 [44–114]; P < 0.001) and the ratio of sFlt-1 to PlGF was significantly higher (6.3 [3.4–15.7] vs. 3.1 [1.8–5.8]; P < 0.001) in women who later developed preeclampsia. The addition of the ratio of PlGF to sEng or the ratio of sFlt-1 to PlGF to a logistic model containing established risk factors (area under the curve [AUC], 0.813) significantly improved the predictive value (AUC, 0.850 and 0.846, respectively; P < 0.01) and significantly improved reclassification according to the integrated discrimination improvement index (IDI) (IDI scores 0.086 and 0.065, respectively; P < 0.001).CONCLUSIONSThese data suggest that angiogenic and antiangiogenic factors measured during the second trimester are predictive of preeclampsia in women with type 1 diabetes. The addition of the ratio of PlGF to sEng or the ratio of sFlt-1 to PlGF to established clinical risk factors significantly improves the prediction of preeclampsia in women with type 1 diabetes.

Automated measurement of sFlt1, PlGF and sFlt1/PlGF ratio in differential diagnosis of hypertensive pregnancy disorders

Objectives: The utility of angiogenic and antiangiogenic biomarkers as diagnostic tools in preeclampsia (PE) has been shown in previous studies. Our study’s aim was to evaluate the use of automated measurement of sFlt1, PlGF and their ratio (sFlt1/PlGF) in differential diagnosis of hypertensive pregnancy disorders. Patients/Methods: Sixty-four patients with PE/HELLP, 18 with pregnancy-induced hypertension (PIH), 22 with gestational proteinuria (GP) and 232 controls were investigated. The PE/HELLP group was divided into mild PE (mPE, n = 31), severe PE (sevPE, n = 20), superimposed PE (supPE, n = 7) and HELLP syndrome (n = 6). sFlt1 and PlGF were measured in serum samples on an automated platform. Statistical analysis was performed using parametric and non-parametric methods, ROC analysis and logistic regression method. Results: PE patients showed higher sFlt1 and ratio and lower PlGF than controls (median ± SEM in pg/mL; 10 888 ± 878 versus 2456 ± 116; 268 ± 39 versus 16 ± 2 and 68 ± 6 versus 439 ± 37, each p < 0.001), subgroups showed similar differences in ratios (median ± SEM; supPE: 202 ± 110; mPE: 137 ± 27; sevPE: 497 ± 91; HELLP syndrome: 254 ± 72 versus controls 16 ± 2, each p < 0.001). ROC analysis showed best performance for sFlt1/PlGF (AUC all PE: ratio 96.4%, sFlt1 92.8%, PlGF 92.4%, supPE: ratio 93.6%, mPE: ratio 94.8%, sevPE: ratio 99.4%, HELLP: ratio 98.6%, each versus controls). Patients with PIH and GP showed significant differences compared to controls (p ≤ 0.01, respectively), mPE (p ≤ 0.007), sevPE (p < 0.001) and HELLP syndrome (p ≤ 0.003). Conclusion: The automated measurement of sFlt1/PlGF is a reliable diagnostic tool in differential diagnosis of hypertensive pregnancy disorders and gives additional valuable information for clinical management.

Cord Blood Soluble fms-Like Tyrosine Kinase 1 and Placental Growth Factor in Preterm Infants with Maternal Preeclampsia

Objectives: The purpose of this study was to investigate the relationship of cord blood levels of soluble fms-like tyrosine kinase 1 (sFlt-1), placental growth factor (PlGF), and vascular endothelial growth factor (VEGF) in preterm infants with maternal preeclampsia. Methods: Thirty six preterm infants born at Ewha Womans University Mokdong Hospital from January 2006 to August 2006 were studied after prior parental consent at mid-pregnancy. sFlt-1, PlGF, and VEGF levels in the cord blood of preterm neonate, with or without maternal preeclampsia, were measured using enzyme-linked immunosorbent assay. Results: There was no difference in sFlt-1 between infants with and without maternal preeclampsia. Infants with maternal preeclampsia had significantly lower PlGF levels (P=0.035) and higher sFlt-1/PlGF ratio (P=0.080) with borderline significance. Cord blood VEGF levels were not related to maternal preeclampsia. Infants with maternal preeclampsia had lower birth weight (P=0.030), lower neonatal platelet count without statistical significance (P=0.064) and more likely to be small for gestational age (P=0.057). Neonatal platelet count was significantly correlated with cord blood PlGF levels (r=0.674, P=0.032). Conclusion: Increased sFlt-1/PlGF ratio and decreased PlGF may not only be related to the pathophysiology of maternal preeclampsia but also affect the neonatal platelet count and birth weight. (Ewha Med J 2013;36(2):118-125) Received April 22, 2013, Accepted July 5, 2013

Soluble Fms-like Tyrosine Kinase 1 Is a Novel Predictor of Brain Natriuretic Peptide Elevation

Soluble fms-like tyrosine kinase 1 (sFlt-1) is an endogenous inhibitor of vascular endothelial growth factor, which is involved in cardiovascular remodeling and atherosclerosis development. To examine the predictive role of sFlt-1 levels in patients with asymptomatic heart failure, we measured circulating sFlt-1 in patients with or without coronary artery disease (CAD). We analyzed 88 Japanese patients with CAD or patients at high risk for atherosclerosis and who were undergoing total risk management for cardiovascular disease prevention. Circulating sFlt-1 levels correlated with the increase in plasma brain natriuretic peptide levels (ΔBNP) from baseline to the observed levels 5 years later in CAD patients, patients with previous myocardial infarction, and men. ΔBNP levels correlated with sFlt-1 levels in the high-sFlt-1 patients with CAD (r = 0.511, P < 0.01). In all patients, end-systolic volume index (ΔESVI) increased in correlation with a decrease in left ventricular ejection fraction (ΔEF) in the long-term observation, independent of their history of myocardial infarction (ΔESVI = 2.5 mL/m(2) increase/year). Baseline level of sFlt-1 was independent of ΔESVI or ΔEF. The present 5-year observational study demonstrated that high sFlt-1 levels predicted moderate increases in BNP levels in CAD patients. Moreover, ΔBNP was correlated with ΔESVI/year in CAD patients with high-sFlt-1 levels. These data suggest that high sFlt-1 levels may be an effective biomarker to predict the progression of heart failure in patients with CAD.

Angiogenic factors in maternal circulation and preeclampsia with or without fetal growth restriction

To study associations of placental growth factor (PlGF) and soluble fms-like tyrosine kinase 1 (sFlt-1) in maternal circulation with the risk of preeclampsia with and without fetal growth restriction. Nested case-control study. A cohort of 29 948 pregnant women in Norway. Cases were identified through linkage to the Medical Birth Registry of Norway. We selected 69 preterm and 36 term preeclampsia cases with delivery of a small-for-gestational-age (SGA) infant, 83 preterm and 154 term preeclampsia cases without SGA delivery, and 384 normotensive controls. We measured PlGF and sFlt-1 in maternal serum samples from each trimester. Odds ratios of preeclampsia subtypes by tertile categories of PlGF and sFlt-1. Low (lowest third) PlGF and sFlt-1 levels in the first trimester, and low (lowest third) increase in PlGF and strong (highest third) increase in sFlt-1 from first to second trimester were associated with increased risk of preterm preeclampsia, both with and without SGA offspring. For term preeclampsia with SGA offspring, the associations were similar to the findings for preterm preeclampsia. For term preeclampsia without SGA offspring, low increase in PlGF from first to second trimester and high sFlt-1 in the third trimester were associated with increased risk. Low PlGF and high sFlt-1 levels in maternal circulation are associated with subsequent development of preeclampsia, regardless of whether fetal growth is affected or not. For term preeclampsia without fetal growth restriction, the imbalance in angiogenic factors seems to appear later in pregnancy than for preterm preeclampsia.

Air Pollution Exposure and Markers of Placental Growth and Function: The Generation R Study

Background: Air pollution exposure during pregnancy might affect placental growth and function, perhaps leading to pregnancy complications.Objective: We prospectively evaluated the associations of maternal air pollution exposure with markers of placental growth and function among 7,801 pregnant women in the Netherlands.Methods: We estimated levels of particulate matter ≤ 10 µm in aerodynamic diameter (PM10) and nitrogen dioxide (NO2) at the home address for different periods during pregnancy using dispersion modeling techniques. Pro- and anti-angiogenic factors [placental growth factor (PlGF) and soluble fms-like tyrosine kinase 1 (sFlt-1), respectively] were measured in first- and second-trimester maternal blood and in fetal cord blood samples at delivery. Pulsatility index of the uterine and umbilical arteries was measured by Doppler ultrasound in second and third trimester, and notching was assessed in third trimester. Placenta weight and birth weight were obtained from medical records.Results: Higher PM10 and NO2 exposure levels were associated with lower second-trimester maternal sFlt-1 and PlGF levels. PM10 and NO2 exposures averaged over total pregnancy were associated with higher sFlt-1 and lower PlGF levels in fetal cord blood, consistent with an anti-angiogenic state. PM10 and NO2 exposures were not consistently associated with second- or third-trimester placental resistance indices. NO2 exposure was associated with third-trimester notching (odds ratio 1.33; 95% CI: 0.99, 1.78 per 10-µg/m3 increase in the prior 2 months). PM10 and NO2 exposures were associated with lower placenta weight (–11.8 g; 95% CI: –20.9, –2.7, and –10.7 g; 95% CI: –19.0, –2.4, respectively, per 10-µg/m3 increase in the prior 2 months), but not with placenta to birth weight ratio.Conclusions: Our results suggest that maternal air pollution exposure may influence markers of placental growth and function. Future studies are needed to confirm these findings and explore the maternal and fetal consequences.

PP058. The additive effect of plasma levels of sFlt-1/PLGF ratio following the risk classification using both blood pressure levels and uterine artery blood flow impedance in the second trimester on the later occurrence of preeclampsia

The multivariate model including circulating levels of soluble fms-like tyrosine kinase 1 (sFlt-1)/placental growth factor (PlGF) ratios, maternal factors, blood pressure (BP) levels and uterine artery (UtA) doppler in the first to second trimester has been reported to be clinically useful to predict PE more accurately. However, the effects of levels of sFlt-1/PlGF ratio after the stratification of women using two major risk factors for PE, BP levels and UtA blood flow imdedance (BFI) have not been evaluated. Our aim was to evaluate the additive effect of plasma levels of sFlt-1/PlGF ratio following the risk classification using both mean blood pressure (MBP) levels and the combination of two UtABFI, mean pulsatility index (mPI) and mean notch depth index (mNDI), on the later occurrence of PE. 1161 women were recruited into a prospective cohort study during 2004 and 2008. Clinical BPs were measured twice during 16 and 23 weeks, UtA doppler was performed twice during 16 and 23 weeks, and the mPI and mNDI was measured. Plasma samples were drawn once at 20-23weeks, and were stored at -20°C until use. The levels of sFlt-1/PlGF ratio were measured by automated electrochemiluminescent immunoassay (Roche Diagnostics K.K.). The cutoff value of mean BP (MBP) was determined as 91.3mmHg using ROC curve, and that of sFlt-1/PlGF ratio was 13.0, the 97.5th percentile of log10(sFlt-1/PlGF) at 20-23 weeks in normal pregnant women. If the mPI was <90th percentile of the gestational-age specific reference range of mPI, or the mNDI was <90th percentile of the gestational-age specific reference range of mNDI, we defined that the UtABFI was low; if the mPI was ⩾90th percentile and the mNDI was ⩾90th percentile, we defined that the UtABFI was high. When women were stratified to 4 groups: low BP and low UtABFI, high BP but low UtABFI, high UtABFI but low BP, high BP and high UtABFI, the PPVs were 0.7%, 6.9%, 6.2% and 39.1%, respectively. In women with low BP and low UtABFI, the high sFlt-1/PlGF changed the PPV to 11.1%; the interval from the sampling to the onset of PE in women with high sFlt-1/PlGF ratio was significantly shorter than in those with low sFlt-1/PlGF ratio (mean±SD [weeks]: 5.9±1.5 vs. 16.5±2.1, p<0.01). In women with high BP but low UtABFI, the high sFlt-1/PlGF changed the PPV to 18.2%; the interval from the sampling to the onset of PE in women with high sFlt-1/PlGF ratio was significantly shorter than in those with low sFlt-1/PlGF ratio (8.0±5.7 vs. 12.6±3.7, p<0.05). Although these effects of sFlt-1/PlGF ratio on the occurrence of PE were not confirmed in women with high BP and high UtABFI, PE occurred in all women with three risk factors (5/5), and the interval from the sampling to the onset of PE was6.8±4.1 weeks. Women with both high BP and high UtABFI, especially those with additional risk of high sFlt-1/PlGF ratio, were the highest risk of PE. In the lowest risk group of low BP and low UtABFI, the addition of sFlt-1/PlGF ratio improved the PPV and the interval from the sampling to the onset of PE. These results clearly indicated the clinical importance of measuring sFlt-1/PlGF ratio in addition to BP levels and UtABFI in all pregnant women in the second trimester.

Angiogenic imbalance and plasma lipid alterations in women with preeclampsia from a developing country

Background: An imbalance between anti-angiogenic factors (e.g. soluble vascular endothelial growth factor receptor-1 (s-FLT1) and soluble endoglin (s-Eng)) and pro-angiogenic factors (e.g. placental growth factor (PlGF)) as well as increased oxidized low-density lipoprotein (ox-LDL) concentrations have been associated with preeclampsia (PE). Risk factors associated with the development of PE, however, are known to be different between developed and developing countries. The aim of the study was to determine the levels of s-FLT1, s-Eng, PIGF, and ox-LDL in women with PE from a developing country. Methods: A multi-center case–control study was conducted. One hundred and forty three women with PE were matched by age and parity with 143 healthy pregnant women without cardiovascular or endocrine diseases. Before delivery, blood samples were taken and serum was stored until analysis. Results: Women with PE had lower concentrations of PIGF (p < 0.0001) and higher concentrations of s-Eng (p = 0.001) than healthy pregnant women. There were no differences between the groups regarding ox-LDL or s-FLT1. Women with early onset PE had higher s-FLT1 concentrations (p = 0.0004) and lower PIGF concentrations (p < 0.0001) than their healthy pregnant controls. Women with late onset PE had higher concentrations of s-Eng (p = 0.005). Women with severe PE had higher concentrations of s-Eng (p = 0.0008) and ox-LDL (p = 0.01), and lower concentrations of PIGF (p < 0.0001). Conclusions: Women with PE from a developing country demonstrated an angiogenic imbalance and an increased rate of LDL oxidation. Findings from this study support the theory that PE is a multifactorial disease, and understanding differences in these subpopulations may provide a better target to approach future therapies.