KRYPTOR-automated angiogenic factor assays and risk of preeclampsia-related adverse outcomes

Objective: To evaluate KRYPTOR assays for circulating soluble fms-like tyrosine kinase-1 (sFlt1) and placental growth factor (PlGF) in risk assessment of adverse outcomes in women with suspected preeclampsia. Methods: We studied 412 women carrying a singleton pregnancy from a previous study cohort who were evaluated for suspected preeclampsia. Another 434 nonpreeclamptic patients with plasma samples drawn throughout pregnancy were used to derive normative data. Plasma sFlt1 and PlGF levels were measured on the automated KRYPTOR platform and evaluated for prediction of adverse maternal and perinatal outcomes within 2 weeks. Normative values were used to create a ratio of markers and these values were reported as multiples of median (MoM) for women with and without adverse outcomes. The KRYPTOR assay results were also compared with previously reported measurements obtained using the automated Elecsys platform. Results: Among participants presenting at <34 weeks (N = 110), patients with subsequent adverse outcome had higher sFlt1, lower PlGF, and higher sFlt1/PlGF ratio compared with women without adverse outcomes: the median (25th, 75th centile) sFlt1 (pg/ml), 9030 (3197, 12,140) versus 1976 (1248, 2937); PlGF (pg/ml), 36 (16, 111) versus 318 (108, 629); and ratio, 285.6 (32.2, 758.5) versus 6.1 (2.3, 20.3) (all p < 0.0001). Higher sFlt1/PlGF ratio correlated negatively with timing of delivery (r = ?0.60, p < 0.001) and the risk of adverse outcomes was markedly elevated among women in highest tertile compared with lower tertile (odds ratio, 14.77; 95% confidence interval (CI), 4.28–51.00). The addition of sFlt1/PlGF ratio (≥85) to hypertension and proteinuria significantly improved the prediction for subsequent adverse outcomes (AUC 0.89 (95% CI): 0.82, 0.95) for hypertension, proteinuria, and sFlt1/PlGF (AUC = 0.75 (0.65, 0.85)) for hypertension alone (p = 0.002). Compared with normative controls, women who were evaluated for preeclampsia without adverse outcomes had higher MoM for sFlt1/PlGF ratio; these values were further elevated in women with adverse outcomes. sFlt1/PlGF ratios measured on the KRYPTOR platform were highly correlated with measurements obtained using Elecys platform (r = 0.97, p < 0.001). Conclusions: In women with suspected preeclampsia presenting prior to 34 weeks of gestation, KRYPTOR assays for circulating sFlt1 and PlGF when used in conjunction with standard clinical evaluation performs well in the prediction of adverse maternal and perinatal outcomes occurring within 2 weeks of presentation.     

Serum sFlt1:PlGF Ratio,PlGF, and Soluble Endoglin Levels in Gestational Proteinuria

Objective: It was recently reported that both a high soluble fms-like tyrosine kinase 1 (sFlt1): placental growth factor (PlGF) ratio (sFlt1:PlGF ratio) and high soluble endoglin (sEng) levels are related to the later occurrence of preeclampsia. We compared the serum sFlt1:PlGF ratio, PlGF and sEng levels in women with gestational proteinuria (GP) to those in women with preeclampsia. Methods: Seven women with GP and 34 women with preeclampsia were recruited in this study. The 95^th percentile values in the reference curves of sFlt1, sFlt1:PlGF ratio and sEng, and the 5^th percentile values in the reference curve of PlGF were respectively set as the cutoff values. Results: The incidence rates of a high sFlt1:PlGF ratio, low PlGF and high sEng in women with GP were 57%, 29% and 86%, respectively, whereas those in women with preeclampsia were 94%, 77%, and 88%, respectively (p?=?0.028, p?=?0.024, and p?=?1.000, respectively). The incidence rates of a both high sFlt1:PlGF ratio and high sEng in women with GP and preeclampsia were 57% and 88%, respectively (p?=?0.082). Conclusion: The majority of women with GP showed both increases of the sFlt1:PlGF ratio and sEng, thus suggesting some women with GP may represent subclinical preeclampsia. In addition, women with GP showed a significantly lower sFlt1:PlGF ratio and higher PlGF level than those with preeclampsia, suggesting that the PlGF level is a key regulator for developing hypertension in some pregnant women, even with increases of both sFlt1:PlGF ratio and sEng levels.     

Angiogenic biomarkers for prediction of early preeclampsia onset in high-risk women

Abstract

Objective: Chronic hypertension, pregestational diabetes mellitus, history of prior preeclampsia and obese nulliparity are maternal conditions associated with increased preeclampsia risk. Whether altered maternal angiogenic factor levels allow for prediction of pending disease is unclear. Our objective was to evaluate angiogenic factors for early preeclampsia prediction in high-risk women.

Methods: Serial serum specimens were collected from 157 women at high preeclampsia risk and 50 low-risk controls between 23 and 36 weeks gestation in 3 windows (23–27.6, 28–31.6, and 32–35.6 weeks) in a two-center observational cohort. Soluble fms-like tyrosine kinase-1 (sFlt1), placental growth factor (PlGF) and soluble endoglin (sEng) were measured by ELISA.

Results: Multivariate parsimonious logistic regression analyses using backward elimination for prediction of early-preeclampsia (diagnosed?<?34 weeks) found the best-fitting model included the predictors (1) sFlt1 measured in the second window (28–31.6 weeks) with AUC 0.85, sensitivity 67% and specificity 96% and (2) sFlt1 measured in the first window (23–27.6 weeks) and sEng change between first and second window with AUC 0.91, sensitivity 86% and specificity 96%.

Conclusions: Two-stage sampling screening protocol utilizing sFlt1 and sEng is promising for prediction of preeclampsia diagnosed before 34 weeks. Larger studies are needed to confirm these findings.     

Soluble Endoglin for the Prediction of Preeclampsia in a High Risk Cohort

Objectives. To evaluate soluble endoglin (sEng) and the soluble fms-like tyrosine kinase 1 (sFlt1) to placental growth factor (PlGF) ratio for the prediction of preeclampsia in high-risk women, and to evaluate differences in sEng between women with high-risk singleton and multiple gestation pregnancies. Study Design. We collected serial serum specimens from 119 women at high preeclampsia risk. sEng, sFlt1 and PlGF were measured by ELISA. Results. Among subjects who did not develop preeclampsia, mean serum sEng was significantly higher in those with multiple gestation pregnancies vs. high-risk singletons. Among women with singleton gestations, mean serum sEng was higher in subjects who developed early-onset (<34 weeks) and late-onset (≥ 34 weeks) preeclampsia, as compared with subjects without preeclampsia, from 22 weeks and 28 weeks gestation onward, respectively. The within-woman rate of change of sEng was also higher in women who later developed preeclampsia. Conclusions. sEng is higher in women with multiple gestations vs. high-risk singleton pregnancies. In high-risk women, serum sEng is increased prior to preeclampsia onset.     

Circulating anti-angiogenic factors during hypertensive pregnancy and increased risk of respiratory distress syndrome in preterm neonates

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% 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, 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 midpregnancy were substantially higher in women whose infants developed RDS.     

Second trimester anti-angiogenic proteins and preeclampsia

OBJECTIVE: To measure the relationships between soluble fms-like tyrosine kinase-1 (sFlt1), soluble endoglin (sEng) and preeclampsia. STUDY DESIGN: We utilized a nested case-control study comprised of 211 preeclamptic women and 213 normotensive women with primiparous singleton pregnancies enrolled from ≥13 and <27 gestational weeks among the Danish National Birth Cohort of 100,000 women. Relationships between sFlt1, sEng and preeclampsia were estimated using smoothing splines in generalized linear models, adjusting for maternal age, body mass index, pre-existing hypertension, smoking, and gestational age. MAIN OUTCOME MEASURES: Preeclampsia was confirmed by an International Classification of Diseases (ICD) discharge diagnosis of 637.03, 637.04 637.09, 637.19 (ICD-8) or DO14 to DO15 (ICD-10) in the National Hospital Discharge Registry. In this sample, few cases delivered small for gestational age infants (8.1%) and the mean gestational age at delivery was term (38.2 ± 2.3 weeks). RESULTS: Doublings in the expressions of sFlt1 and sEng were associated with 39% (95% CI = 3%, 86%) and 74% (95% CI = 1%, 198%) increased risks of preeclampsia respectively. CONCLUSIONS: We conclude that second trimester high sFlt1 and sEng levels were possibly associated with an increased risk of preeclampsia after adjustment for maternal factors traditionally associated with the syndrome.     

Maternal plasma concentrations of sST2 and angiogenic/anti-angiogenic factors in preeclampsia

Abstract

Objectives: Angiogenic/anti-angiogenic factors have emerged as one of the promising biomarkers for the prediction of preeclampsia. Since not all patients with preeclampsia can be identified by these analytes, the search for additional biomarkers continues. The soluble form of ST2 (sST2), a protein capable of binding to interleukin (IL)-33 and thus contributing to a Th1-biased immune response, has been reported to be elevated in maternal plasma of women with preeclampsia. The aims of this study were to examine: (1) differences in maternal plasma concentrations of sST2 and IL-33 between women diagnosed with preeclampsia and those having uncomplicated pregnancies; (2) the relationship between sST2, umbilical and uterine artery Doppler velocimetry, and the severity of preeclampsia; and (3) the performance of sST2 and angiogenic/anti-angiogenic factors in identifying patients with preeclampsia at the time of diagnosis.

Methods: This cross-sectional study included women with preeclampsia (n?=?106) and women with an uncomplicated pregnancy (n?=?131). Plasma concentrations of sST2, IL-33, soluble vascular endothelial growth factor receptor (sVEGFR)-1, soluble endoglin (sEng) and placental growth factor (PlGF) were determined by enzyme linked immune sorbent assay. Area under the receiver operating characteristic curve (AUC) for the identification of preeclampsia was examined for each analyte.

Results: (1) Patients with preeclampsia had a higher mean plasma concentrations of sST2 than those with an uncomplicated pregnancy (p?<?0.0001), while no significant difference in the mean plasma concentration of IL-33 between the two groups was observed; (2) the magnitude of this difference was greater in early-onset, compared to late-onset disease, and in severe compared to mild preeclampsia; (3) sST2 plasma concentrations did not correlate with the results of uterine or umbilical artery Doppler velocimetry (p?=?0.7 and p?=?1, respectively) among women with preeclampsia; (4) sST2 correlated positively with plasma concentrations of sVEGFR1-1 and sEng (Spearman’s Rho?=?0.72 and 0.63; each p?<?0.0001), and negatively with PlGF (Spearman’s Rho?=??0.56, p?<?0.0001); and (5) while the AUC achieved by sST2 and angiogenic/anti-angiogenic factors in identifying women with preeclampsia at the time of diagnosis were non-significantly different prior to term (<37 weeks of gestation), thereafter the AUC achieved by sST2 was significantly less than that achieved by angiogenic/anti-angiogenic factors.

Conclusions: Preeclampsia is associated with increased maternal plasma concentrations of sST2. The findings that sST2 concentrations do not correlate with uterine or umbilical artery Doppler velocimetry in women with preeclampsia suggest that elevated maternal plasma sST2 concentrations in preeclampsia are not related to the increased impedance to flow in the utero-placental circulation. The performance of sST2 in identifying preeclampsia at the time of diagnosis prior to 37 weeks of gestation was comparable to that of angiogenic/anti-angiogenic factors. It remains to be elucidated if an elevation of maternal plasma sST2 concentrations in pregnancy is specific to preeclampsia.     

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

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

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

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

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

Serum angiogenic profile in abnormal placentation

Objective: To evaluate the circulating soluble fms-like tyrosine kinase 1 (sFlt1), placental growth factor (PlGF) and vascular endothelial growth factor (VEGF) levels in women with abnormal placentation and to compare the data with the results of women with normal pregnancy.

Material and methods: Serum biomarkers of angiogenesis and maternal and perinatal characteristics of 68 pregnant women, all in the third trimester, who were diagnosed to have vaginal bleeding due to complete placenta previa with and without concomitant placenta accreta, increta and percreta as the study group and 30 pregnant women without any placentation abnormality who eventually delivered at ≥37 weeks of gestational age as the control group were evaluated.

Results: There was no statistical difference in the maternal serum values of sFlt1, PlGF, sFlt1/PlGF ratio and VEGF in groups with placental abnormality as compared to controls. Not even a single case of preeclampsia and intrauterine fetal growth restriction was encountered in the study group.

Conclusion: We demonstrated that regardless of the localization and the degree of the myometrial invasion of the placenta in the uterus, the circulatory biomarkers of angiogenesis and vascularization were comparable.     

Soluble fms-like tyrosine kinase-1 and soluble endoglin in HIV-associated preeclampsia

Objective

Preeclampsia is characterized by endothelial dysfunction combined with increased concentrations of sFlt1, which antagonizes the biological effects of VEGF and PlGF, and of sEng, which antagonizes TGFβ₁. This angiogenic imbalance may have a role in its etiology. This study evaluated the expression of VEGF, PlGF, sFlt1 and sEng amongst third trimester pregnancies in women with HIV-associated pre-eclampsia.

Method

Serum and placental tissue were obtained from 76 pregnancies in women who were normotensive and HIV negative (N−) or positive (N+), and in women who were pre-eclamptic and HIV negative (P−) or positive (P+). The serum and placental samples were quantitatively evaluated using ELISAs and RT-PCR respectively.

Results

Placental sFlt1 expression differed significantly between the N− and P− groups (p = 0.001). Similarly, sEng expression differed between the N− and P− groups (p = 0.001). No significant effect was shown between HIV status and pregnancy. Serum sFlt1 (p = 0.02) and sEng (p = 0.001) were up-regulated in the P− compared to the N− groups. Similarly, no significant effect was shown between HIV status and pregnancy. Both VEGF and PlGF did not differ significantly between groups. Notably, sEng expression was elevated in both placenta and serum, whilst placental sFlt1 differed from serum. A weak but significant correlation between serum and placental concentration for sFlt1, sEng and PlGF (r = 0.26, p = 0.031; r = 0.42, p < 0.001 and r = −0.3, p = 0.014) was observed.

Conclusions

This novel study demonstrates an up-regulation of serum sFlt1 and sEng in preeclamptic compared to normotensive groups irrespective of the HIV status of the pregnancy. This implicates a contributory role of sFlt1 and sEng in preeclampsia development. The serum reduction of sFlt1 and sEng within the HIV positive compared to HIV negative cohorts may imply a neutralization of the immune hyperreactivity of preeclampsia.     

Relationship between nulliparity and preeclampsia may be explained by altered circulating soluble fms-like tyrosine kinase 1

Objective: To test the hypothesis that the risk of preeclampsia in nulliparous women may be due to an anti-angiogenic state. Methods: Maternal serum samples obtained in the third trimester from nulliparous (n?=?86) and multiparous (n?=?165) singleton uncomplicated pregnancies were analyzed for levels of angiogenic factors – soluble fms like tyrosine kinase 1 (sFlt1) and placental growth factor (PlGF) by enzyme-linked immunosorbent assay (ELISA). Results: For nulliparous and multiparous pregnancies, serum sFlt1 levels were 12?732?±?832 and 10?162?±?666 (p?=?0.020), serum PlGF levels were 215?±?15 and 249?±?14 (p?=?0.093) (all reported as mean SD in pg/ml) and mean ratios of sFlt1/PlGF were 93?±?12 and 62?±?5 (p?=?0.023), respectively. Adjustment for maternal age and fetal birth weight did not alter the results. Conclusions: Nulliparous pregnancies had higher circulating sFlt1 levels and sFlt1/PlGF ratios than multiparous pregnancies, suggesting an association with an angiogenic imbalance. Taken together with the pathogenic role of anti-angiogenic factors in preeclampsia, our data may be one explanation for the epidemiological observation that nulliparity is a risk factor for the development of preeclampsia.     

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

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

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

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

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

A comparison of the diagnostic utility of the sFlt-1/PlGF ratio versus PlGF alone for the detection of preeclampsia/HELLP syndrome

Objective: The Elecsys^® immunoassay sFlt-1/PlGF ratio and the Triage^® PlGF assay were compared (in a prospective, multicenter, case-control study) for diagnosis of preeclampsia/hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome. Methods: Women in European perinatal care centers with singleton pregnancies were enrolled: 178 cases had confirmed preeclampsia and 391 controls had normal outcome. Patients in the preeclampsia/HELLP syndrome group were matched pairwise by gestational week to healthy controls (1:2). Maternal blood samples were analyzed using (a) fully automated Elecsys PlGF and Elecsys sFlt-1 immunoassays with two cutoffs (early-onset [<34 weeks] ≤33, ≥85; late-onset [≥34 weeks] ≤33, ≥110), and (b) Triage PlGF immunoassay (single cutoff). Diagnostic performance and utility were assessed. Results: Respectively, 83 and 95 women had early-onset or late-onset preeclampsia/HELLP syndrome. The overall diagnostic performance of the Elecsys immunoassay sFlt-1/PlGF ratio (area under the curve [AUC] 0.941) was higher than for Triage PlGF (AUC 0.917). The Elecsys immunoassay sFlt-1/PlGF ratio sensitivity and specificity was: 94.0% (95% confidence interval [CI] 86.5–98.0) and 99.4% (95% CI: 96.8–99.9) for early-onset preeclampsia; and 89.5% (95% CI: 81.5–94.8) and 95.4% (95% CI: 91.7–97.8) for late-onset preeclampsia. The Triage assay sensitivity and specificity was: 96.4% (95% CI: 89.8–99.3) and 88.5% (95% CI: 82.8–92.8) (early-onset); and 90.5% (95% CI: 83–96) and 64.5% (95% CI: 57.8–70.9) (late onset). Conclusions: The fully automated Elecsys immunoassay sFlt-1/PlGF ratio provides improved diagnostic utility over the Triage PlGF assay with improved specificity for the clinical management of pregnant women with suspected preeclampsia/HELLP syndrome.     

Peripheral arterial tonometry and angiogenic biomarkers in preeclampsia

ABSTRACT

Objective: To evaluate changes in vascular function and serum biomarkers in women with and without preeclampsia (PE) to create a model for the easier and more precise diagnosis of PE in the future. Methods: Endothelial function and arterial stiffness were evaluated using peripheral arterial tonometry and concentrations of placental growth factor (PlGF), soluble fms like tyrosine kinase 1 (sFlt-1) and soluble endoglin (sEng) were determined by immunoassay. Results: Arterial stiffness deteriorates and endothelial function is better in women with PE compared with a healthy pregnancy. Women who developed PE had a decreased PlGF and PlGF/(sFlt-1+ sEng) ratio and an increased sEng, and sFlt-1/PlGF ratio. Conclusion: Peripheral arterial analysis did provide additional information beyond serum biomarkers in the diagnosis of PE.     

The use of angiogenic factors in discriminating preeclampsia: are they ready for prime time?

Objectives.?We sought to evaluate the association between soluble fms-like tyrosine kinase 1 (sFlt1) and endoglin (ENG) and preeclampsia in an urban population, to develop a discriminatory model, and evaluate the association of these biomarkers with small for gestational age (SGA).

Methods.?Cases are prospectively identified with preeclampsia. Controls are term patients without preeclampsia. Commercially available ELISAs were used to measure levels of sFlt1, ENG, and placental growth factor (PlGF). Log-transformed levels were compared and multivariable logistic regression analyses were performed to control for confounders. Receiver operating characteristic curves were developed.

Results.?In cases (n?=?86) compared to controls (n?=?288), sFlt1 (p?=?0.24) levels were no different. However, ENG levels were higher (p?<?0.001), and PlGF levels were lower (p?<?0.001). Further, levels of sFlt1 had poor discriminatory ability between cases and controls [AUC?=?0.56, (0.48–0.63)]. The best model to discriminate between groups included clinical risk factors, ENG, and PlGF [AUC?=?0.89, (0.85–0.92)].

Conclusions.?Unlike recent reports, this study suggests that sFlt1 may have limited diagnostic utility in predicting preeclampsia, especially term disease.     

An analysis on the roles of angiogenesis-related factors including serum vitamin D,soluble endoglin (sEng), soluble fms-like tyrosine kinase 1 (sFlt1), and vascular endothelial growth factor (VEGF) in the diagnosis and severity of late-onset preeclampsia

Aim: The aim of this study was to evaluate the roles of proangiogenic factors including serum vitamin D and vascular endothelial growth factor (VEGF) and anti-angiogenic factors including soluble endoglin (sEng) and soluble fms-like tyrosine kinase 1 (sFlt1) in the diagnosis and severity of late-onset preeclampsia.

Materials and methods: The study was conducted at Yuzuncu Yil University Research and Education Hospital Department of Gynecology and Obstetrics. The study included a patient group of 40 women with late-onset preeclampsia who were pregnant at?≥32 weeks of gestation according to the last menstrual period (LMP) or ultrasonographic fetal biometric measurement and a control group of 40 healthy pregnant women who presented to our clinic for routine pregnancy examination and were at the same age and gestational period with those in the patient group. The two groups were compared in terms of maternal age, gravida, parity, week of gestation, systolic/diastolic blood pressure, total protein in spot urine sample, 24-h urine protein, white blood cell (WBC), hemoglobin (Hgb), platelet count, urea, creatinine, liver function tests (AST, ALT, LDH), vitamin D₃, 25(OH) vitamin D₃, 1,25(OH) vitamin D₃, sEng, sFlt1, and VEGF levels, mode of delivery, the infant APGAR score at 1 and 5?min after delivery, and infant weight at delivery.

Results: The groups were similar in terms of age, gravida, parity, week of gestation, serum vitamin D₃, 25(OH) vitamin D₃, 1,25(OH)₂ vitamin D₃ and VEGF levels, and infant weight at delivery (p?>?0.05). Systolic/diastolic blood pressure, total protein in spot urine sample, 24-h urine protein, WBC, Hgb, serum urea, creatine, AST, ALT, and LDH were significantly higher in the preeclamptic group compared to the healthy group (p?p?3, 25(OH) vitamin D₃, and 1,25(OH)₂ vitamin D₃ levels. The sEng level was higher in the women with severe preeclampsia compared to the women with mild preeclampsia (p?3, 25(OH) vitamin D₃, and 1,25(OH)₂ vitamin D₃ levels between the subgroups of preeclampsia (p?>?0.05).

Conclusion: Both sEng and sFlt1 levels are remarkably high in patients with late-onset preeclampsia; however, only sEng may be a useful tool in the determination of the severity of preeclampsia.     

A subset of patients destined to develop spontaneous preterm labor has an abnormal angiogenic/anti-angiogenic profile in maternal plasma: Evidence in support of pathophysiologic heterogeneity of preterm labor derived from a longitudinal study

Objective.?An imbalance between angiogenic and anti-angiogenic factors in maternal blood has been observed in several obstetrical syndromes including preeclampsia, pregnancies with fetal growth restriction and fetal death. Vascular lesions have been identified in a subset of patients with spontaneous preterm labor (PTL). It is possible that PTL may be one of the manifestations of an anti-angiogenic state. The aim of this study was to determine if patients prior to the clinical diagnosis of PTL leading to preterm delivery had plasma concentrations of angiogenic and anti-angiogenic factors different from normal pregnant women.

Study Design.?This longitudinal nested case–control study included normal pregnant women (n?=?208) and patients with PTL leading to preterm delivery (n?=?52). Maternal blood samples were collected at 6 gestational age intervals from 6 to36.9 weeks of gestation. The end point (time of diagnosis) of the study, ‘True PTL’, was defined as patients presenting with PTL and delivered within 1 day. Plasma concentrations of sVEGFR-1, sVEGFR-2, sEng and PlGF were determined by ELISA. Analysis was performed with both cross-sectional and longitudinal (mixed effects model) approaches.

Results. (1) Plasma sEng concentration in patients destined to develop PTL was higher than that in normal pregnant women from 15–20 weeks of gestation. The difference became statistical significant at 28 weeks of gestation, or approximately 5–10 weeks prior to the diagnosis of ‘true PTL’. (2) Backward analysis suggests that plasma concentrations of PlGF and sVEGFR-2 were lower, and those of sVEGFR-1 were higher in patients with PTL than in normal pregnant women less than 5 weeks prior to the diagnosis of ‘true PTL’; and (3) Plasma concentrations of sEng and sVEGFR-1 were higher and those of PlGF and sVEGFR-2 were lower in patients diagnosed with PTL and delivery within 1 day than in normal pregnant women who delivered at term.

Conclusion.?The changes in sEng are demonstrable several weeks prior to the onset of preterm parturition. In contrast, the changes in the other angiogenic proteins are present close to the onset of PTL and delivery. This observation supports the view that an imbalance of angiogenic factors participates in the pathophysiology of spontaneous preterm parturition.     

The association of circulating angiogenic factors and HbA1c with the risk of preeclampsia in women with preexisting diabetes

Objective: To assess whether glycemic control, soluble fms-like tyrosine kinase 1 (sFlt1) and placental growth factor (PlGF) were associated with the development of preeclampsia (PE) or gestational hypertension (GHTN) in women with preexisting diabetes. Methods: Maternal circulating angiogenic factors (sFlt1 and PlGF) measured on automated platform were studied at four time points during pregnancy in women with diabetes (N?=?159) and reported as multiples of the median (MOM) of sFlt1/PlGF ratio (median, 25th–75th percentile) noted in non-diabetic non-hypertensive control pregnant population (N?=?139). Diagnosis of PE or GHTN was determined by review of de-identified clinical data. Results: PE developed in 12% (N?=?19) and GHTN developed in 23% (N?=?37) of the women with diabetes. Among diabetic women without PE or GHTN, median sFlt1/PlGF levels at 35–40 weeks was threefold higher than in non-diabetic controls [MOM 3.21(1.19–7.24), p?=?0.0001]. Diabetic women who subsequently developed PE had even greater alterations in sFlt1/PlGF ratio during the third trimester [MOM for PE at 27–34 weeks 15.18 (2.37–26.86), at 35–40 weeks 8.61(1.20–18.27), p?≤?0.01 for both windows compared to non-diabetic controls]. Women with diabetes who subsequently developed GHTN also had significant alterations in angiogenic factors during third trimester; however, these findings were less striking. Among women with diabetes, glycosylated hemoglobin (HbA1c) during the first trimester was higher in subjects who subsequently developed PE (7.7 vs 6.7%, p?=?0.0001 for diabetic PE vs diabetic non-PE). Conclusions: Women with diabetes had a markedly altered anti-angiogenic state late in pregnancy that was further exacerbated in subjects who developed PE. Altered angiogenic factors may be one mechanism for the increased risk of PE in this population. Increased HbA1c in the first trimester of pregnancies in women with diabetes was strongly associated with subsequent PE.     

Late-onset preeclampsia is associated with an imbalance of angiogenic and anti-angiogenic factors in patients with and without placental lesions consistent with maternal underperfusion

Objective: An imbalance between maternal angiogenic/anti-angiogenic factors concentrations has been observed in preeclampsia (PE) and other obstetrical syndromes. However, the frequency of pathologic findings in the placenta and the changes in maternal plasma angiogenic/anti-angiogenic factor concentrations differ between late- and early-onset PE. The aim of this study was to determine if the maternal plasma concentrations of placental growth factor (PlGF), soluble endoglin (sEng), and soluble vascular endothelial growth factor receptor-1 and 2 (sVEGFR-1 and sVEGFR-2) are different in late-onset PE with and without placental pathologic findings consistent with maternal underperfusion. Study design: A cross-sectional study was conducted including 64 uncomplicated women and 66 women with late-onset PE (>34 weeks) who had blood samples and placenta available for pathologic examination. Patients with late-onset PE were divided into those with and without placental histologic findings consistent with maternal underperfusion as proposed by the Society for Pediatric Pathology. Maternal plasma concentrations of PlGF, sEng, sVEGFR-1 and sVEGRF-2 were determined by ELISA. Non-parametric statistics were used for analysis. Results: 1) the prevalence of placental histological findings consistent with maternal underperfusion among women with late-onset PE was higher than that of those with an uncomplicated pregnancy (47% (31/66) vs. 7.8% (5/64), respectively; p?<?0.01); 2) patients with late-onset PE and histological findings consistent with maternal underperfusion had a significantly lower median plasma concentration of PlGF, plasma PlGF/sVEGFR-1 ratio and plasma PlGF/sEng ratio than those with late-onset PE without placental underperfusion lesions (each p?<?0.05); 3) the most common pathological findings in the placenta of patient with PE were lesions consistent with villous changes (77%, 24/31); and 4) isolated vascular lesions in the placenta were found only in 2 cases (6.5%), and the rest had a combination of villous and vascular lesions. Conclusions: Nearly half of the patients with late-onset PE have placental lesions consistent with maternal underperfusion. These lesions are associated with an imbalance in the maternal concentration of angiogenic/anti-angiogenic factors. We propose that there is a link between maternal underperfusion and an anti-angiogenic state characterized by the changes in the concentrations of angiogenic and anti-angiogenic factors in women with late onset PE.     

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.