Urinary angiogenic factors cluster hypertensive disorders and identify women with severe preeclampsia

Urinary sFlt-1 and PlGF as preeclampsia predictors: sFlt-1/creatinine ratio improves the prediction value

OBJECTIVES

To evaluate the correlation between maternal serum and urinary soluble Fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) levels and to assess their potential value in preeclampsia and fetal growth restriction.

STUDY DESIGN

This case-control longitudinal prospective study was performed in 49 singleton pregnant women, divided into two clinical groups, low risk pregnancy (n = 23) and pregnancy complicated by preeclampsia (n = 26). Maternal serum and urinary sFlt-1 and PlGF levels were quantified by electrochemiluminescence. Every patient underwent an ultrasound for fetal biometry. Doppler assessment was done when estimated fetal weight was under the 10th centile. ROC curves were used to evaluate the predictive capability of serum and urinary angiogenic biomarkers and their ratios on preeclampsia. Linear regression was used to compare the values of serum and urinary sFlt-1 and PlGF and their ratios.

RESULTS

Urine biomarkers were positively associated with their serum values, being the best associated urinary PlGF (R2 = 0.73), which also showed the highest predictive capability of preeclampsia of urine biomarkers (AUC 0.866). The predictive capability of urinary sFlt-1 was much lower (AUC 0.640), but increased when adjusting by serum creatinine, a more precise parameter (AUC 0.863).

CONCLUSIONS

Urinary PlGF could be a lesser invasive alternative to circulating biomarkers to monitor pregnancies complicated with preeclampsia that need repeated controls of their pregnancy complication. Urinary sFlt-1 values need adjustment by serum creatinine to be reliable.

Potential urinary biomarkers in preeclampsia: a narrative review

INTRODUCTION

Preeclampsia (PE) is a highly relevant pregnancy-related disorder. An early and accurate diagnosis is crucial to prevent major maternal and neonatal complications and mortality. Due to the association of kidney dysfunction with the pathophysiology of the disease, urine samples have the potential to provide biomarkers for PE prediction, being minimally invasive and easy to perform. Therefore, searching for novel biomarkers may improve outcomes. This narrative review aimed to summarize the scientific literature about the traditional and potential urinary biomarkers in PE and to investigate their applicability to screen and diagnose the disorder.

METHODS

A non-systematic search was performed in PubMed/MEDLINE, Scopus, and SciELO databases.

RESULTS

There is significant divergence in the literature regarding traditionally used serum markers creatinine, cystatin C, and albuminuria, accuracy in PE prediction. As for the potential renal biomarkers investigated, including vascular epithelial growth factor (VEGF), placental growth factor (PlGF), and soluble fms-like tyrosine kinase (sFlt-1), urinary levels of PlGF and sFtl-1/PlGF ratio in urine seem to be the most promising as screening tests. The assessment of the global load of misfolded proteins through urinary congophilia, podocyturia, and nephrinuria has also shown potential for screening and diagnosis. Studies regarding the use of proteomics and metabolomics have shown good accuracy, sensitivity, and specificity for predicting the development and severity of PE.

CONCLUSION

However, there are still many divergences in the literature, which requires future and more conclusive research to confirm the predictive role of urinary biomarkers in pregnant women with PE.

Predictive value of the sFlt‑1/PlGF ratio in women with suspected preeclampsia: An update (Review)

Preeclampsia (PE) is a major complication of pregnancy with an incidence rate of 2‑8% and is a leading cause of maternal mortality and morbidity. The various consequences of severe preeclampsia for the fetus, neonate and child include intrauterine growth retardation (IUGR), fetal hypoxia, oligohydramnios, intrauterine fetal demise, increased perinatal mortality and morbidity, neurodevelopmental disorders and even irreversible brain damage (cerebral palsy). A number of studies have demonstrated that differences in maternal serum concentrations of angiogenic factors between preeclampsia and normotensive pregnancies can be used as biomarkers, either alone or in combination with other markers, to predict the development of PE. The presence in the maternal circulation of two proteins of placental origin, placental growth factor (PlGF) and soluble fms‑like tyrosine kinase 1 (sFlt‑1), has been shown to be of clinical value, as the sFlt‑1/PlGF ratio appears to be the optimal predictive tool for the development of PE. The measurement of their concentration in maternal serum in screening models, serves as predictive marker for the development of PE or IUGR later in gestation. However, further research is required to improve its clinical applicability and provide guidelines for its use worldwide to achieve more consistent clinical management of women with PE.

Comparison of clinical outcomes and biochemical markers in normal and preeclamptic pregnancies: a prospective cohort study

Background

Preeclampsia (PreE), the de novo onset of hypertension and proteinuria at 20 weeks of gestation, is a leading cause of maternal and fetal morbidity and mortality. This study compared inflammatory biomarkers in PreE and normal pregnancies using paired samples of mothers and neonates.

Methods

Twenty normal pregnant and 27 PreE patients were monitored for biomarkers, neonatal outcomes, and placental morphologies. Fetal and maternal serum levels of vascular endothelial growth factor (VEGF), placental growth factor (PlGF), soluble endoglin (sENG), and soluble fms-like tyrosine kinase-1 (sFLT-1) were measured by enzyme-linked immunosorbent assay.

Results

Placental thickness was 25 mm in early PreE subjects compared to 32 mm in late PreE subjects (P < 0.05). Placental volume was 296 cm3 in early PreE compared to 393 cm3 in late PreE (P < 0.05). The average hospital stay for PreE babies was longer (20 ± 5 days) compared to babies from normal pregnancies (2 ± 1 days; P < 0.05). PreE babies had a lower Ponderal index (2.28 ± 0.3) than those from normal pregnancies (2.95 ± 0.2; P < 0.05). sENG and sFLT-1 had cord values like the maternal values, while VEGF and PlGF did not.

Conclusion

PreE alters the intrauterine environment by activating chemical mediators that result in maternal and fetal complications.

Utility of sFtl-1 and Placental Growth Factor Ratio for Adequate Preeclampsia Management

Introduction: The pathophysiology of preeclampsia is represented by placental ischemia and the release of angiogenic factors. Recent research suggests that using the value of the sFtl-1/PIGF ratio is more accurate for monitoring angiogenic activity. The aim of this study consists in assessing the clinical utility of the sFtl-1/PIGF ratio in determining the diagnosis and severity of preeclampsia. Material and Methods: In our study a descriptive and prospective plan was used for analyzing the specific value of the sFtl-1/PIGF ratio in women with preeclampsia and in women with gestational hypertension, depending on the gestational age and severity. Results: The study included 59 women with preeclampsia and 25 women with gestational hypertension. The mean value of the sFtl-1/PIGF ratio of pregnant women with preeclampsia was 209.2 pg/mL, while in the gestational hypertension group, the mean value of the sFtl-1/PIGF ratio was 46.08 pg/mL. The difference between the value of the sFtl-1/PIGF ratio of the group with preeclampsia and the gestational hypertension group was > 67 (pg/mL), with a sensitivity of 86.44% and a specificity of 92.00%. Significant differences were found between the median values of the sFtl-1/PIGF ratio in pregnant women with severe preeclampsia in the early-onset subgroup compared to those in the late-onset subgroup (307 pg/mL, and 98 pg/mL, respectively, p = 0.009 < α = 0.05). Conclusions: The sFtl-1/PIGF ratio may be an alternative method for diagnosing preeclampsia and it can provide data about this condition's severity.

A Study of Role of Urinary Congophilia in Early Detection of Preeclampsia

Introduction Preeclampsia and eclampsia are important causes of maternal morbidity. Preeclapmtic women secrete misfolded proteins in the urine. Buhimschi et al had developed a new test for diagnosis of preeclampsia. This test is based on staining of misfolded protein with Congo red dye. Misfolded proteins are derived from syncytiotrophoblast microparticles (STBMs). These STBM are membrane bound vesicles and contain misfolded proteins. In preeclampsia, glomeruli of kidneys are disrupted and these damaged protein reach the urine.

Aim and Objective This study aimed to investigate the role of urinary congophilia in early prediction of preeclampsia.

Materials and Methods This test was done in 250 pregnant women attending the Gynaecological Outpatient Department. Urine sample of early morning was taken and test was done in the Department of Biochemistry. The included pregnant women were of gestational age between 14 and 18 weeks. The staining of urine with Congo red dye was done and washed with methanol. The retention of dye was interpreted with naked eye. The more retention of dye, the more chances of developing preeclampsia later. The patients were followed-up till delivery. The patents who developed preeclampsia later part of pregnancy were recorded. Mean arterial pressure (MAP) and past history and body mass index were also recorded.

Results Out of 250 patients, 30 developed preeclampsia later. A total of 34 patients were having positive urinary congophilia and only 20 patients developed preeclampsia later. MAP more than 90 mm Hg is abnormal but 66.7% of patients who developed preeclampsia had MAP >90 mm Hg. In 16.7% of patients, who developed preeclampsia later, had positive past history of hypertension. In 66.7% of patients, who were positive for urinary congophilia, later developed preeclampsia.

Conclusion Preeclampsia and eclampsia are important causes of maternal mortality and morbidity. So, early detection can prevent complications and timely management. Urinary congophilia is one of such test which can help in early prediction of preeclampsia. If it is combined with past maternal history and MAP, it gives more good results. The detection rate is much higher if signs and symptoms of preeclampsia are noticed timely.

Soluble Flt1 levels are associated with cardiac dysfunction in Black women with and without severe preeclampsia

Background: We evaluate soluble fms-like tyrosine kinase-1 (sFlt-1) levels and cardiac function during pregnancy and postpartum among Black women with and without preeclampsia. Study design: Prospective longitudinal cohort study from 2015 to 2017 of Black women with preterm severe preeclampsia and normotensive pregnant controls.We obtained echocardiograms and sFlt-1 levels during pregnancy and postpartum. Results: 93 Black women were included (43 cases, 50 controls). Higher sFlt1 levels were correlated with worse longitudinal strain, diastolic dysfunction, decreased ventricular-arterial coupling, and increased chamber and arterial elastance at the time of preeclampsia diagnosis and postpartum. Conclusions: Higher sFlt1 levels are associated with cardiovascular dysfunction during pregnancy and postpartum.

Integrated EC-SERS Chip with Uniform Nanostructured EC-SERS Active Working Electrode for Rapid Detection of Uric Acid

Toxemia of pregnancy is a very dangerous disease for pregnant women. The mortality rate of toxemia of pregnancy is close to 10% to 15%. Early detection of pregnancy toxemia is to monitoring uric acid concentration in urine. The current mainstream method for detecting uric acid requires an enzyme (urate oxidase), which needs to be stored in a low-temperature environment, and the method requires complex chemical steps, which takes a longer time and more samples. In this study, we propose an integrated miniature three-electrode electrochemical surface-enhanced Raman spectroscopy chip (EC-SERS chip) suitable for rapid EC-SERS detection applications. The integrated microfluidic reservoir on the chip makes it easy to use, which is very suitable for rapid detection applications. The SERS active working electrode for the proposed integrated EC-SERS chip is a nanocone array polycarbonate (PC) substrate decorated with an evenly distributed and tightly packed array of gold nanospheres. It showed good uniformity and can be easily reproduced. The integrated EC-SERS chip is very small compared to the traditional electrochemical cell, which reduces the sample volume required for the testing. In addition, the chip is for one-time use only. It eliminates the need to clean electrochemical cells for reuse, thereby reducing the possibility of contamination and inaccurate detection. Various low-concentration Rhodamine 6G (R6G) solutions were tested to verify the performance of the developed EC-SERS chip. Experimental results showed that the proposed EC-SERS chip has a strong enhancement factor of up to 8.5 × 10⁶ and a very good EC-SERS uniformity (the relative standard deviation of EC-SERS intensity is as low as 1.41%). The EC-SERS chip developed has been further tested for the detection of uric acid in synthetic urine. The results showed that the EC-SERS signal intensity has a highly linear relationship with the logarithm of the uric acid concentration in synthetic urine, which indicates that the developed EC-SERS chip is suitable for the quantitative detection of uric acid in synthetic urine. Therefore, the developed EC-SERS chip is very promising to be used in routine and early diagnosis of pregnancy toxemia and may be used in many other medical tests, food safety, and biotechnology applications.

Preeclampsia: Pathophysiology and management

Preeclampsia is a pregnancy-related multisystem disorder, frequently encountered pregnancy-related medical complications next to gestational diabetes mellitus. It is the onset of hypertension during pregnancy. The preeclampsia can be of two types, placental or maternal preeclampsia. Among these two types former, i.e., placental preeclampsia is more severe than the latter. According to the recent survey by National Health Portal of India, the incidence of preeclampsia is about 8-10 % among pregnant women. Though our understanding of preeclampsia has improved in recent years, the development and interpretation of the clinical tests remain difficult for preeclampsia. Hence, we have made an attempt to understand the pathophysiology, associated conditions/consequences, treatment and management/prevention of the condition in this review.

Urinary Placental Growth Factor for Prediction of Placental Adverse Outcomes in High-Risk Pregnancies

OBJECTIVE

To evaluate whether urinary levels of placental growth factor (PlGF) during pregnancy are associated with the subsequent development of composite adverse outcomes (preeclampsia, fetal growth restriction, placental abruption, perinatal death, maternal death) occurring at less than 34 weeks of gestation.

METHODS

This is a preplanned ancillary study of the Heparin-Preeclampsia trial, a randomized trial in pregnant women with a history of severe early-onset preeclampsia (less than 34 weeks of gestation). In the parent study, all women were treated with aspirin and then randomized to receive either low-molecular-weight (LMW) heparin or aspirin alone. For this substudy we measured urinary levels of PlGF and urinary creatinine at the following gestational windows: 10-13 6/7, 14-17 6/7, 18-21 6/7, 22-25 6/7, 26-29 6/7, 30-33 6/7, and 34-37 6/7 weeks of gestation.

RESULTS

Urine samples were available from 187 patients: LMW heparin plus aspirin (n=93) and aspirin alone (n=94). The two groups had comparable baseline characteristics and had similar adverse composite outcomes at less than 34 weeks of gestation (14/93 [15.1%] vs 11/94 [11.7%]; P=.50). There were no significant differences in urine PlGF levels in the patients who received LMW heparin plus aspirin compared with those who received aspirin alone. However, median [interquartile range] urinary PlGF/creatinine concentrations (pg/mg) measured at mid-pregnancy (22-26 weeks of gestation) were significantly lower among women who developed composite adverse outcome at less than 34 weeks of gestation (42.7 [32.4-80.8] vs 255.6 [118.7-391.8] P<.001) and significantly lower among women who developed preeclampsia at less than 34 weeks of gestation (42.7 [27.5-80.7] vs 244.6 [112.9-390.6] P<.001). For a fixed false-positive rate of 10% the sensitivity of urinary PlGF concentrations at mid-pregnancy was 75.2% (area under the curve 0.93) for the subsequent development of composite adverse outcomes.

CONCLUSION

Decreased urinary PlGF at mid-gestation (22-26 weeks of gestation) is associated with the subsequent development of preeclampsia-related adverse outcomes at less than 34 weeks of gestation.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT00986765.

Abnormal expression and clinical significance of 25-hydroxyvitamin D and sFlt-1 in patients with preeclampsia

Objective

To determine the association between levels of serum 25-hydroxyvitamin D (25[OH]D) and soluble fms-like tyrosine kinase 1 (sFlt-1) in patients with preeclampsia.

Methods

Clinical and demographic data were collected from patients with preeclampsia and healthy pregnant controls. Serum 25(OH)D and sFlt-1 levels were evaluated by enzyme-linked immunosorbent assay and their correlations were determined using Spearman’s rank correlation coefficient. Associations between serum 25(OH)D and sFlt-1 levels and disease severity and clinical parameters were evaluated.

Results

Significantly lower serum 25(OH)D and higher sFlt-1 levels were observed in patients with preeclampsia (n = 100) versus controls (n = 100), and 25(OH)D was inversely correlated with sFlt-1 in patients with preeclampsia. Serum 25(OH)D levels were reduced, while sFlt-1 concentration was increased in patients with severe versus mild preeclampsia. Serum 25(OH)D levels were reduced in late-onset versus early-onset severe preeclampsia. Patients with preeclampsia who had lower serum 25(OH)D or elevated sFlt-1 levels showed significantly higher blood pressure indexes versus those with higher 25(OH)D or lower sFlt-1.

Conclusions

Low serum 25(OH)D and high sFlt-1 may be candidate biomarkers for preeclampsia diagnosis and prognosis.

Reference centiles for maternal placental growth factor levels at term from a low-risk population

INTRODUCTION

Placental growth factor (PLGF) is a biomarker of placental function. The aim of this study was to define reference ranges for maternal PLGF levels in a normotensive cohort ≥36 + 0 weeks.

METHOD

Prospective observational data from Mater Mothers' Hospital, Brisbane. PLGF levels were measured in women at ≥36 + 0 weeks with singleton, non-anomalous pregnancies. Women with hypertension and fetal growth restriction were excluded. PLGF (pg/mL) was assayed using DELFIA® Xpress (PerkinElmer Inc). The Generalised Additive Model for Location, Shape and Scale (GAMLSS) method was used for the calculation of gestational age-adjusted centiles. Data analysis was performed with Stata 13 (StataCorp, LLC) and R software (R Foundation for Statistical Computing, Vienna, Austria). In all women, PLGF was measured within 2 weeks of delivery.

RESULTS

The study cohort comprised of 845 women (36 weeks n = 73, 37 weeks n = 230, 38 weeks n = 214, 39 weeks n = 172, 40 weeks n = 115, 41weeks n = 41). PLGF levels were negatively correlated with gestational age (r = -0.20, p < 0.001). Median PLGF levels dropped significantly from 36 weeks to 41 weeks (169.0 pg/mL to 96.6 pg/mL, p < 0.001). Gestational age specific maternal PLGF centiles were reported using fractional polynomial additive term and Box-Cox t distribution. PLGF did not perform adequately as a predictive test for adverse perinatal outcomes (AUC <0.6).

DISCUSSION

We have created gestational centile reference ranges for maternal PLGF from a normotensive cohort. These novel data suggest maternal PLGF levels decline ≥36 + 0 weeks. The utility of PLGF as a predictor of adverse perinatal outcomes at term, should be further investigated with clinical trials.

Exploring strengths and limits of urinary D-chiro inositol phosphoglycans (IPG-P) as a screening test for preeclampsia: A systematic review and meta-analysis

Preeclampsia is a severe complication of human pregnancy as it leads to significant maternal and perinatal mortality and morbidity worldwide. A prompt recognition of women that develop this syndrome can improve clinical management, increase surveillance and, finally, improve outcomes. Different methods (based on history, ultrasound, serum and urinary biomarkers) were proposed a screening tests for this disease but their performance showed limited results. Urinary inositol phosphoglycans P-type (IPG-P) were shown to identify in advance most of the women who will develop preeclampsia in case-control and longitudinal studies, so we undertook a systematic review and meta-analysis of published studies. Seven studies met the entry criteria so were evaluated. All case-control studies showed excellent statistical performances in a quality statistical assessment. The meta-analysis considered three longitudinal, prospective studies that showed high sensitivity and specificity with ranges of 0.82- 0.99 and 0.90-1.00, respectively. Univariate measures of accuracy revealed a positive and negative likelihood ratio respectively of 3.61 (95% CI 1.56-5.67) and -2.35 (95% CI -3.79 to -0.91). By univariate approach, we found a pooled logarithm of diagnostic odds ratio of 6.15 (95% CI 2.64-9.67). A limitation of this analysis is that, although conducted in different settings (UK, Italy, France, South Africa, and Mauritius) and different clinical groups, they were based on a single academic group. According to our findings, IPG-P test showed very encouraging results as a rapid noninvasive screening test for preeclampsia. Further studies are needed to verify and to validate the reported findings.

A cross sectional study to assess the sFlt-1:PlGF ratio in pregnant women with and without preeclampsia

BACKGROUND

Preeclampsia is a multisystem disorder characterized by vascular endothelial malfunction occurring after 20 weeks of gestation. Placental soluble fms-like tyrosine kinase-1 (sFlt-1) is an antiangiogenic factor and placental growth factor (PlGF) is a potent angiogenic factor. The imbalance between these factors during placenta and fetal development has been shown to play a role in endothelial damage in preeclampsia. Preeclampsia is the leading cause of maternal mortality in Nepal. This study was designed to compare the sFlt1:PLGF ratio in pregnant women with and without preeclampsia attending Tribhuvan University Teaching Hospital (TUTH).

METHOD

An observational cross-sectional study was performed in the Gynecology and Obstetrics Department of TUTH involving forty-four subjects with preeclampsia and forty-four age- and gestational-week-matched normal pregnant subjects as controls. Blood pressure, urinary protein levels, serum sFlt-1 levels, serum PlGF levels and the sFlt-1:PlGF ratio was compared in both the cases and control. The concentrations of sFlt-1 and PlGF were measured with commercially available ELISA kits. SPSS ver. 20.0 was used to analyze the data.

RESULTS

There was no significant difference in age or gestational age in either study group. The ratio of the sFlt-1 and PlGF concentrations was significantly higher in women with preeclampsia (31.6 ± 9.6) than in the controls (3.2 ± 1.3). Likewise, diastolic blood pressure was significantly associated (p-value 0.000), whereas the severity of proteinuria was not associated (p-value 0.773) with the sFlt-1:PlGF ratio in women with preeclampsia. The significantly higher ratio (35.51 ± 8.1 versus 25.4 ± 8.7) was found in women with preeclampsia who developed complications than the group of women with preeclampsia who did not develop complication.

CONCLUSION

The sFlt-1:PlGF ratio is significantly higher in Nepalese women with preeclampsia than in normal controls and this finding can be applied for further planned clinical trials.

Urinary placental growth factor in preeclampsia and fetal growth restriction: An alternative to circulating biomarkers?

AIM

To correlate plasma and urinary soluble fms-like tyrosine kinase 1 (sFlt-1) and placental growth factor (PIGF) in preeclampsia (PE) and fetal growth restriction (FGR) and assess the performance in detecting established disease.

METHODS

A cross-sectional case-control study recruited 26-40 weeks gestation pregnancies into four clinical groups: normal pregnancy, PE, PE + FGR, and FGR. enzyme-linked immunosorbent assay (ELISA) measurements of urinary and plasma sFlt-1 and PlGF levels were performed. Urinary levels of sFlt-1 and PIGF were normalized to creatinine. Spearman's rank correlation was used to assess the association between plasma and urinary levels of sFlt-1 and PIGF, and receiver operating characteristic graphs were used to quantify the performance of each individual marker and their ratios in predicting normal versus pathological pregnancies affected by preeclampsia and/or FGR.

RESULTS

There was a significant correlation between plasma PlGF and urinary PlGF (r = 0.718, P < 0.001) in all groups. In the pathological groups, plasma sFlt-1 and urinary sFlt-1 as well as plasma sFlt-1: PIGF ratio and urinary sFlt-1: PlGF ratio were higher, but plasma PIGF and urinary PlGF were lower when compared to normal pregnancy. Plasma PIGF and plasma sFlt-1: PlGF ratio was comparable in performance to urinary PlGF and urinary sFlt-1: PIGF ratio for the diagnosis of preeclampsia and/or FGR.

CONCLUSION

Urinary PIGF can be used as an alternative to circulating biomarkers in preeclampsia and FGR. Plasma sFlt-1, PlGF and sFlt-1: PlGF ratio as well as urinary PIGF and sFlt-1: PlGF ratio can be used to differentiate between normal pregnancy and pregnancies complicated by preeclampsia and FGR.

Congo Red Dot Paper Test for Antenatal Triage and Rapid Identification of Preeclampsia

BACKGROUND

Proteins in the urine of women with preeclampsia (PE) bind Congo Red dye (urine congophilia). We sought to determine the diagnostic performance of a paper-based point-of-care test detecting urine congophilia for rapid triage and diagnosis of PE.

METHODS

Prospective cohort study conducted in 346 consecutive pregnant women evaluated for PE in the Labour and Delivery triage unit at our institution. The Congo Red Dot (CRD) Paper Test (index test) was performed on fresh urine samples. The CRD Paper Test results were compared to an expert adjudicated diagnosis in each case. The accuracy of the CRD Paper Test was also compared to urine and serum analytes (placental growth factor and soluble fms-like tyrosine kinase-1) previously proposed as diagnostic aids for PE.

FINDINGS

During the first triage visit, 32% (112/346) of women received a clinical diagnosis of PE. Yet, 63% (217/346) were admitted for in-patient diagnostic work-up or delivery. The CRD Paper Test was positive in 25% (86/346) of the cases. Adjudication confirmed PE in 28% (96/346) of all cases. The CRD Paper Test outperformed measured serum and urine markers (80·2% sensitivity, 89·2% specificity, 92·1% negative predictive value, 86·7% accuracy). The pre-test, positive and negative post-test probabilities were 27·7%, 74·0%, and 8·0%, respectively. Of women who were discharged undelivered, 38% (133/346) had at least one additional triage visit and the interval between the last negative and first positive CRD Paper Test was 12 (interquartile range, [5-34]) days.

INTERPRETATION

The CRD Paper Test is a simple, non-invasive, "sample-in/answer-out" point-of-care clinical tool for rapid identification of PE.

FUNDING

Saving Lives at Birth Program and NICHD.

Diagnosis and antibiotic treatment of group a streptococcal pharyngitis in children in a primary care setting: impact of point-of-care polymerase chain reaction

BACKGROUND

To compare the sensitivity and specificity of the recommended 2-step rapid antigen detection test (RADT) with confirmatory culture vs the point-of-care (POC) polymerase chain reaction (PCR) Roche cobas® Liat® Strep A test for detection of group A Streptococcus (GAS) in pediatric patients with pharyngitis, and to investigate the impact of these tests on antibiotic use in a large pediatric clinic.

METHODS

This prospective, open-label study was conducted at a single site during fall/winter 2016-2017. A total of 275 patients aged 3 to 18 years with symptoms of pharyngitis had a throat-swab specimen analyzed using RADT, POC PCR, and culture. The sensitivity, specificity, and percentage agreement (95% CI) between assays and a laboratory-based nucleic acid amplification test were calculated. DNA sequencing was used to adjudicate discrepancies. The RADT or POC PCR result was provided to clinicians on alternating weeks to compare the impact on antibiotic use.

RESULTS

A total of 255 samples were evaluated; 110 (43.1%) were GAS positive. Sensitivities (95% CI) for POC PCR, RADT, and culture were 95.5% (89.7-98.5%), 85.5% (77.5-1.5%), and 71.8% (62.4-80.0%), respectively. Specificities (95% CI) for POC PCR, RADT, and culture were 99.3% (96.2-99.98%), 93.7% (88.5-97.1%), and 100% (97.5-100%), respectively. Compared with RADT, POC PCR resulted in significantly greater appropriate antibiotic use (97.1% vs 87.5%; P = .0065).

CONCLUSION

Under real-world conditions, RADT results were less specific and culture results were less sensitive than found in established literature and led to increased rates of inappropriate antibiotic use. POC PCR had high sensitivity and specificity and rapid turnaround times, and led to more appropriate antibiotic use.

TRIAL REGISTRATION

ID number ISRCTN84562679 . Registered October 162,018, retrospectively registered.

Superhydrophobic silver film as a SERS substrate for the detection of uric acid and creatinine

Superhydrophobic silver films were fabricated by silver-mirror reaction and surface functionalization with thiol. The thiol-functionalization significantly improved the hydrophobic property of the Ag films (AFS), and their contact angle values slightly increased with the extension of a thiol alkyl chain, reaching about 160°. The surface-enhanced Raman scattering (SERS) detection capacity of these films were investigated, and AFS-Dodec showed the best substrate for R6G molecule detection with the concentration limit of 10^-11 M. AFS functionalized with dodecanethiol (AFS-Dodec) was applied for the SERS detection of uric acid and creatinine, it exhibited good linear dependence relationship between the Raman intensity and analyte concentration in the concentration range of 5~1000 μM.

Clinical Presentation of Preeclampsia and the Diagnostic Value of Proteins and Their Methylation Products as Biomarkers in Pregnant Women with Preeclampsia and Their Newborns

Preeclampsia (PE) is a disorder which affects 1-10% of pregnant women worldwide. It is characterised by hypertension and proteinuria in the later stages of gestation and can lead to maternal and perinatal morbidity and mortality. Other than the delivery of the foetus and the removal of the placenta, to date there are no therapeutic approaches to treat or prevent PE. It is thus only possible to reduce PE-related mortality through early detection, careful monitoring, and treatment of the symptoms. For these reasons the search for noninvasive, blood-borne, or urinary biochemical markers that could be used for the screening, presymptomatic diagnosis, and prediction of the development of PE is of great urgency. So far, a number of biomarkers have been proposed for predicting PE, based on pathophysiological observations, but these have mostly proven to be unreliable and inconsistent between different studies. The clinical presentation of PE and data gathered for the biochemical markers placental growth factor (PlGF), soluble Feline McDonough Sarcoma- (fms-) like tyrosine kinase-1 (sFlt-1), asymmetric dimethylarginine (ADMA), and methyl-lysine is being reviewed with the aim of providing both a clinical and biochemical understanding of how these biomarkers might assist in the diagnosis of PE or indicate its severity.

Inducible knockout of Syncytin-A gene leads to an extensive placental vasculature deficiency, implications for preeclampsia

Syncytin-1, a human endogenous retroviral envelope gene (HERVW1), is specifically expressed in placental trophoblasts and mediates the formation of syncytiotrophoblasts through a fusogenic activity. Syncytin-1 expression deficiency has been repeatedly observed in preeclamptic/IUGR placentas. Previous gene knockout studies indicated that in mice, complete syncytin-A null mouse embryos died in utero between 11.5 and 13.5days of gestation. However, the complete knockout model could not fully recapitulate the mid- to third-trimester, time-specific syncytin-1 deficiency in preeclampsia patients. To construct a preeclampsia model and to better investigate the function of syncytin in placental development, we created a mouse inducible knockout model of syncytin-1A gene. It was found that the disruption of syncytin-A at E11.5 to E17.5 is associated with significant morphological changes in placentas and fetuses. Moreover, syncytin-A disruption led to extensive vasculature abnormalities in the labyrinth, with irregular distribution and reduced number of fetal microvessels. Moreover, Syncytin-A knockout affected neovascularization-related gene expression in labyrinth and the maternal plasma level of sVEGFR-1, and a dramatic increase of sFlt-1/PlGF ratio. These findings indicate that syncytin-A may be involved in the placenta angiogenesis and potentially, the development of preeclampsia. The new model could be a useful tool for studying the pathogenesis and management of preeclampsia.

Absolute Quantification of Uric Acid in Human Urine Using Surface Enhanced Raman Scattering with the Standard Addition Method

High levels of uric acid in urine and serum can be indicative of hypertension and the pregnancy related condition, preeclampsia. We have developed a simple, cost-effective, portable surface enhanced Raman scattering (SERS) approach for the routine analysis of uric acid at clinically relevant levels in urine patient samples. This approach, combined with the standard addition method (SAM), allows for the absolute quantification of uric acid directly in a complex matrix such as that from human urine. Results are highly comparable and in very good agreement with HPLC results, with an average <9% difference in predictions between the two analytical approaches across all samples analyzed, with SERS demonstrating a 60-fold reduction in acquisition time compared with HPLC. For the first time, clinical prepreeclampsia patient samples have been used for quantitative uric acid detection using a simple, rapid colloidal SERS approach without the need for complex data analysis.

A portable SERS method for the determination of uric acid using a paper-based substrate and multivariate curve resolution

This paper presents a portable quantitative method for the on-site determination of uric acid in urine using surface-enhanced Raman spectroscopy (SERS) and gold nanoparticle-coated paper as a substrate. A procedure was developed for the rapid preparation of cost-effective SERS substrates that enabled the adequate control of a homogeneous active area and the use of small quantities of gold nanoparticles per substrate. The standard addition method and multivariate curve resolution-alternating least squares (MCR-ALS) were applied to compensate for the matrix effect and to address overlapping bands between uric acid and interference SERS spectra. The proposed methodology demonstrated better performance than conventional univariate methods (in terms of linearity, accuracy and precision), a wide linear range (0-3.5 mmol L(-1)) and an adequate limit of detection (0.11 mmol L(-1)). For the first time, a portable SERS method coupled with chemometrics was developed for the routine analysis of uric acid at clinically relevant concentrations with minimal sample preparation and easy extension for the on-site determination of other biomarkers in complex sample matrices.

Impact of maternal serum levels of Visfatin, AFP, PAPP-A, sFlt-1 and PlGF at 11-13 weeks gestation on small for gestational age births

OBJECTIVE

Investigating potential value of maternal serum Visfatin, sFlt-1, PlGF, AFP, PAPP-A levels at first trimester for prediction of small for gestational age (SGA) at birth.

METHODS

Measurements were performed in 20 SGA and 65 control cases. Logistic regression analysis adjusted for age and weeks of pregnancy at data collection was performed to estimate odds ratios (OR), 95% confidence intervals (95% CI) and p values separately for each potential predictor. A multiple regression model was used to assess the impact of all the promising predictors adjusted for each other. Receiver operating characteristic (ROC) analysis was used to indicate the ability to discriminate between SGA cases and controls.

RESULTS

There was an association of serum PlGF levels (OR 0.53 per interquartile range [IQR] increase in PlGF; 95% CI 0.24-1.16), sFlt-1/PlGF ratio (OR 1.42 per IQR increase in sFlt-1/PlGF; 95% CI 1.03-1.96), serum Visfatin levels (OR 0.31 per IQR increase in Visfatin; 95% CI 0.10-0.95) and smoking (OR 4.24; 95% CI 1.10-16.37) with SGA at birth.

CONCLUSIONS

Associations between SGA and lower PlGF, Visfatin levels as well as increased sFlt-1/PlGF ratio and smoking status were detected which may contribute to predict SGA.

Preeclampsia and Vascular Function: A Window to Future Cardiovascular Disease Risk

Preeclampsia affects ∼3%-7% of all pregnancies and is the third leading cause of maternal mortality globally. Growing evidence indicates that preeclampsia results from vascular dysfunction, which also increases the risk for future cardiovascular events. Until recently, preeclampsia was considered a disorder limited to pregnancy, which fully resolved with the delivery of the placenta; however, it is now clear that women with a history of preeclampsia have approximately double the risk of future cardiovascular events compared to women with normotensive pregnancies. The aims of this review were to describe the hemodynamic and vascular changes that occur in normal and preeclamptic pregnancies, to review noninvasive methods to test vascular function, and to discuss the associated increased cardiovascular disease risk related to preeclampsia.

A Prospective Study of Placental Growth Factor Assay as a Novel Biomarker in Predicting Early-Onset Preeclampsia in High-Risk Patients

INTRODUCTION

Preeclampsia is a leading cause of maternal and perinatal mortality and morbidity, but signs and symptoms are non-specific and may vary. The root cause is imbalance of circulating angiogenic factors of placental (syncytiotrophoblast) origin, with consequent low levels of placental growth factor (PlGF) which may aid in diagnosis and prediction of disease.

AIMS AND OBJECTIVES

To study the incidence of women at risk of developing early-onset preeclampsia by plasma placental growth factor biomarker assay in high-risk patients, to assess the maternal outcome in patients with PlGF values below cutoff for presenting gestational age, to calculate sensitivity, specificity, positive predictive value and negative predictive value of PlGF assay in predicting preeclampsia and to conclude whether PlGF biomarker assay can be an effective screening test in high-risk patients for prediction of early-onset preeclampsia.

MATERIALS AND METHODS

The study was carried out in the Department of Obstetrics and Gynecology at a tertiary care center. It is a prospective study, and study period extended from April 2012 to October 2013. One hundred pregnant women with 20- to 34-week gestational age with possible high risk of developing preeclampsia attending the antenatal clinics and high-risk OPDs were screened in the present study after explaining the nature of the study. PLGF concentration was quantitated using plasma and processed in Triage kit device (fluorescence immunoassay device). PLGF concentration was categorized against a specific range for specific gestation, and values below the range or <12 pg/ml were considered screened positives. The cases were followed up till delivery.

RESULTS

Twenty-two cases were screened positive, of which 20 developed preeclampsia with a strong positive prediction value of more than 90 %.

CONCLUSION

PLGF is a strong predictor and a useful assay for early-onset preeclampsia.

Circulating Levels of sFlt1 Splice Variants as Predictive Markers for the Development of Preeclampsia

Angiogenic biomarkers, including soluble fms-like tyrosine kinase 1 (sFlt1), are thought to be predictors of preeclampsia onset; however, improvement is needed before a widespread diagnostic test can be utilized. Here we describe the development and use of diagnostic monoclonal antibodies specific to the two main splice variants of sFlt1, sFlt1-1 and sFlt1-14. These antibodies were selected for their sensitivity and specificity to their respective sFlt1 isoform in a capture ELISA format. Data from this pilot study suggest that sFlt1-1 may be more predictive of preeclampsia than total sFlt1. It may be possible to improve current diagnostic platforms if more specific antibodies are utilized.

Heme oxygenase-1 is critically involved in placentation, spiral artery remodeling, and blood pressure regulation during murine pregnancy

The onset of pregnancy implies the appearance of a new organ, the placenta. One main function of the placenta is to supply oxygen to the fetus via hemoproteins. In this review, we highlight the importance of the enzyme heme oxygenase-1 (HO-1) for pregnancy to be established and maintained. HO-1 expression is pivotal to promote placental function and fetal development, thus determining the success of pregnancy. The deletion of the gene Hmox1 in mice leads to inadequate remodeling of spiral arteries and suboptimal placentation followed by intrauterine growth restriction (IUGR) and fetal lethality. A partial Hmox1 deletion leads to IUGR as well, with heterozygote and wild-type fetuses being born, but Hmox1 (-/-) significantly below the expected Mendelian rate. This strong phenotype is associated with diminished number of pregnancy-protective uterine natural killer (uNK) cells. Pregnant heterozygote females develop gestational hypertension. The protective HO-1 effects on placentation and fetal growth can be mimicked by the exogenous administration of carbon monoxide (CO), a product of heme catalyzed by HO-1. CO application promotes the in situ proliferation of uNK cells, restores placentation and fetal growth, while normalizing blood pressure. Similarly, HO-1 inhibition provokes hypertension in pregnant rats. The HO-1/CO axis plays a pivotal role in sustaining pregnancy and aids in the understanding of the biology of pregnancy and reveals a promising therapeutic application in the treatment of pregnancy complications.

Excretion of urinary orosomucoid 1 protein is elevated in patients with chronic heart failure

Easily screening markers for early detection of chronic heart failure (CHF) are lacking. We identified twenty differently expressed proteins including orosomucoid 1(ORM1) in urine between patients with CHF and normal controls by proteomic methods. Bioinformatics analyses suggested ORM1 could be used for further analysis. After verification by western blotting, the urinary levels of ORM1 were quantified with enzyme-linked immunosorbent assay (ELISA) by correcting for creatinine expression. The ORM1-Cr was significantly elevated in CHF patients than normal controls (6498.83±4300.21 versus 2102.26±1069.24 ng/mg). Furthermore, a Spearman analysis indicated that the urinary ORM1 levels had a high positive correlation with the classification of CHF, and the multivariate analysis suggested that the urinary ORM1 content was associated with the plasma amino-terminal pro- brain natriuretic peptide (NT-proBNP) (OR: 2.106, 95% CI: 1.213–3.524, P = 0.002) and the New York Heart Association (NYHA) classification (OR: 3.019, 95% CI: 1.329–4.721, P<0.001). In addition, receiving operating curve (ROC) analyses suggested that an optimum cut-off value of 2484.98 ng/mg with 90.91% sensitivity and 85.48% specificity, respectively, could be used for the diagnosis of CHF. To sum up, our findings indicate that ORM1 could be a potential novel urinary biomarker for the early detection of CHF.

Protein misfolding, congophilia, oligomerization, and defective amyloid processing in preeclampsia

Preeclampsia is a pregnancy-specific disorder of unknown etiology and a leading contributor to maternal and perinatal morbidity and mortality worldwide. Because there is no cure other than delivery, preeclampsia is the leading cause of iatrogenic preterm birth. We show that preeclampsia shares pathophysiologic features with recognized protein misfolding disorders. These features include urine congophilia (affinity for the amyloidophilic dye Congo red), affinity for conformational state–dependent antibodies, and dysregulation of prototype proteolytic enzymes involved in amyloid precursor protein (APP) processing. Assessment of global protein misfolding load in pregnancy based on urine congophilia (Congo red dot test) carries diagnostic and prognostic potential for preeclampsia. We used conformational state–dependent antibodies to demonstrate the presence of generic supramolecular assemblies (prefibrillar oligomers and annular protofibrils), which vary in quantitative and qualitative representation with preeclampsia severity. In the first attempt to characterize the preeclampsia misfoldome, we report that the urine congophilic material includes proteoforms of ceruloplasmin, immunoglobulin free light chains, SERPINA1, albumin, interferon-inducible protein 6-16, and Alzheimer’s β-amyloid. The human placenta abundantly expresses APP along with prototype APP-processing enzymes, of which the α-secretase ADAM10, the β-secretases BACE1 and BACE2, and the γ-secretase presenilin-1 were all up-regulated in preeclampsia. The presence of β-amyloid aggregates in placentas of women with preeclampsia and fetal growth restriction further supports the notion that this condition should join the growing list of protein conformational disorders. If these aggregates play a pathophysiologic role, our findings may lead to treatment for preeclampsia.

Are there financial savings associated with supplementing current diagnostic practice for preeclampsia with a novel test? Learnings from a modeling analysis from a German payer perspective

OBJECTIVE

To quantify the financial impact of adding a novel serum test to the current diagnostic toolkit for preeclampsia (PE) detection in Germany.

METHODS

A decision-analytic model was created to quantify the economic impact of adding a recently developed novel diagnostic test for PE (Roche Diagnostics, Rotkreuz, Switzerland) to current diagnostic practice in Germany. The model simulated a cohort of 1000 pregnant patients receiving obstetric care and quantified the budget impact of adding the novel test to current German PE detection and management practices.

RESULTS

The model estimates that the costs associated with managing a typical pregnancy in Germany are €941 when the novel test is used versus €1579 with standard practice. This represents savings of €637 per pregnant woman, even when the test is used as a supplementary diagnostic tool. The savings are attributed to the novel test's ability to better classify patients relative to current practice, specifically, its ability to reduce false negatives by 67% and false positives by 71%.

CONCLUSION

The novel PE test has the potential to provide substantial cost savings to German healthcare payers, even when used as an addition to standard practice. Better classification of patients at risk for developing PE and declassification of those that are not compared to current practice leads to economic savings for the healthcare system. Furthermore, by reducing the rates of false-positive and false-negative classification relative to current standard of care, the test helps better target healthcare spending and lowers overall costs associated with PE care.

Low-molecular weight heparin increases circulating sFlt-1 levels and enhances urinary elimination

Rationale

Preeclampsia is a devastating medical complication of pregnancy which leads to maternal and fetal morbidity and mortality. While the etiology of preeclampsia is unclear, human and animal studies suggest that excessive circulating levels of soluble fms-like tyrosine-kinase-1 (sFlt-1), an alternatively spliced variant of VEGF-receptor1, contribute to the signs and symptoms of preeclampsia. Since sFlt-1 binds to heparin and heparan sulfate proteoglycans, we hypothesized that the anticoagulant heparin, which is often used in pregnancy, may interfere with the levels, distribution and elimination of sFlt-1 in vivo.

Objective

We systematically determined serum and urine levels of angiogenic factors in preeclamptic women before and after administration of low molecular weight heparin and further characterized the interaction with heparin in biochemical studies.

Methods and Results

Serum and urine samples were used to measure sFlt-1 levels before and after heparin administration. Serum levels of sFlt-1 increased by 25% after heparin administration in pregnant women. The magnitude of the increase in circulating sFlt-1 correlated with initial sFlt-1 serum levels. Urinary sFlt-1 levels were also elevated following heparin administration and levels of elimination were dependent on the underlying integrity of the glomerular filtration barrier. Biochemical binding studies employing cation exchange chromatography revealed that heparin bound sFlt-1 had decreased affinity to negatively charged surfaces when compared to sFlt-1 alone.

Conclusion

Low molecular weight heparin administration increased circulating sFlt1 levels and enhanced renal elimination. We provide evidence that both effects may be due to heparin binding to sFlt1 and masking the positive charges on sFlt1 protein.

An Elevated Maternal Plasma Soluble fms-Like Tyrosine Kinase-1 to Placental Growth Factor Ratio at Midtrimester Is a Useful Predictor for Preeclampsia

Background. To assess the ability of mid-trimester sFlt-1/PlGF ratio for prediction of preeclampsia in two different Arabic populations. Methods. This study measured levels of sFlt-1, PlGF, and sFlt-1/PlGF ratio at midtrimester in 83 patients who developed preeclampsia with contemporary 250 matched controls. Results. Women subsequently developed preeclampsia had significantly lower PlGF levels and higher sFlt-1 and sFlt-1/PlGF ratio levels than women with normal pregnancies (P < 0.0001 for all). Women who with preterm preeclampsia had significantly higher sFlt-1 and sFlt-1/PlGF ratio than term preeclamptic women (P = 0.01, 0.003, resp.). A cutoff value of 3198 pg/mL for sFlt-1 was able to predict preeclampsia with sensitivity, specificity, and accuracy of 88%, 83.6%, and 84.7%, respectively, with odds ratio (OR) 37.2 [95% confidence interval (CI) 17.7-78.1]. PIGF at cutoff value of 138 pg/mL was able to predict preeclampsia with sensitivity, specificity, and accuracy of 85.5%, 77.2%, and 79.3%, respectively, with OR 20 [95% CI, 10.2-39.5]. The sFlt-1/PIGF ratio at cutoff value of 24.5 was able to predict preeclampsia with sensitivity, specificity, and accuracy of 91.6%, 86.4%, and 87.7%, respectively with OR 67 [95% CI, 29.3-162.1]. Conclusion. Midtrimester sFlt-1/PlGF ratio displayed the highest sensitivity, specificity, accuracy, and OR for prediction of preeclampsia, demonstrating that it may stipulate more effective prediction of preeclampsia development than individual factor assay.

Dysregulation of hydrogen sulfide producing enzyme cystathionine γ-lyase contributes to maternal hypertension and placental abnormalities in preeclampsia

BACKGROUND

The exact etiology of preeclampsia is unknown, but there is growing evidence of an imbalance in angiogenic growth factors and abnormal placentation. Hydrogen sulfide (H2S), a gaseous messenger produced mainly by cystathionine γ-lyase (CSE), is a proangiogenic vasodilator. We hypothesized that a reduction in CSE activity may alter the angiogenic balance in pregnancy and induce abnormal placentation and maternal hypertension.

METHODS AND RESULTS

Plasma levels of H2S were significantly decreased in women with preeclampsia (P<0.01), which was associated with reduced placental CSE expression as determined by real-time polymerase chain reaction and immunohistochemistry. Inhibition of CSE activity by DL-propargylglycine reduced placental growth factorproduction from first-trimester (8-12 weeks gestation) human placental explants and inhibited trophoblast invasion in vitro. Knockdown of CSE in human umbilical vein endothelial cells by small-interfering RNA increased the release of soluble fms-like tyrosine kinase-1 and soluble endoglin, as assessed by enzyme-linked immunosorbent assay, whereas adenoviral-mediated CSE overexpression in human umbilical vein endothelial cells inhibited their release. Administration of DL-propargylglycine to pregnant mice induced hypertension and liver damage, promoted abnormal labyrinth vascularization in the placenta, and decreased fetal growth. Finally, a slow-releasing H2S-generating compound, GYY4137, inhibited circulating soluble fms-like tyrosine kinase-1 and soluble endoglin levels and restored fetal growth in mice that was compromised by DL-propargylglycine treatment, demonstrating that the effect of CSE inhibitor was attributable to inhibition of H2S production.

CONCLUSIONS

These results imply that endogenous H2S is required for healthy placental vasculature and that a decrease in CSE/H2S activity may contribute to the pathogenesis of preeclampsia.

Vasoactive agents for the prediction of early- and late-onset preeclampsia in a high-risk cohort

Background

To evaluate the soluble fms-like tyrosine kinase-1 (sFlt-1), placental growth factor (PlGF), and sFlt-1/PlGF ratio for the prediction of early- and late-onset preeclampsia in a high-risk cohort.

Methods

We studied serial serum samples collected prospectively at 12 + 0 - 14 + 0, 18 + 0 - 20 + 0, and 26 + 0 - 28 + 0 weeks + days of gestation in 6 women who developed early-onset preeclampsia (before 34 weeks of gestation) and in 21 women who developed late-onset preeclampsia (after 34 weeks of gestation) with automated ElecSys 2010 immunoanalyzer (Roche Diagnostics, Germany). Twenty-six high-risk women and 53 women without risk factors with normal pregnancies served as controls.

Results

Serum PlGF concentrations were lower at 18 + 0 to 20 + 0, and 26 + 0 to 28 + 0 weeks of gestation in women who developed early-onset preeclampsia compared to women who developed late-onset preeclampsia and to controls (p < 0.05 for all comparisons). At 18 + 0 to 20 + 0 weeks of gestation area under the receiver-operating characteristic curve (AUC) for serum PlGF was 99.8% (p = 0.0007, 95% CI 99.0-100.0). At 26 + 0 to 28 + 0 weeks of gestation serum sFlt-1/PlGF ratio explicitly detects those women who developed early-onset preeclampsia (AUC 100.0%, p = 0.0007, 95% CI 100–100). Amongst women with late-onset preeclampsia, those who developed severe form of the disease (N = 8) had significantly higher serum sFlt-1 concentrations at all three timepoints (p = 0.004, p = 0.006, and p = 0.003, respectively) compared to women with non-severe form (N = 13).

Conclusions

Low serum PlGF concentration predicts early-onset preeclampsia from the second trimester and elevated serum sFlt-1/PlGF ratio from 26 to 28 weeks of gestation. Elevated serum sFlt-1 concentration in the first trimester in women who later develop late-onset, severe preeclampsia may suggest different etiology compared to the late-onset non-severe form of the disease.

New developments in the pathogenesis of preeclampsia

Preeclampsia affects 3% to 5% of all pregnancies and is a major cause of maternal and perinatal morbidity and mortality worldwide. This disorder is characterized by a constellation of signs and symptoms, most notably new-onset hypertension and proteinuria during the last trimester of pregnancy. In this review, the molecular mechanisms of preeclampsia with an emphasis on the role of circulating antiangiogenic proteins in the pathogenesis of preeclampsia and its complications will be discussed.

Circulating levels of neutrophil gelatinase-associated lipocalin (NGAL) correlate with the presence and severity of preeclampsia

OBJECTIVE

Neutrophil gelatinase-associated lipocalin (NGAL) has emerged as a reliable marker of acute renal injury and is produced at the maternal-fetal interface but its role in preeclampsia has not been systematically examined. This study investigated whether plasma NGAL concentrations changed in patients with preeclampsia at diagnosis compared to normotensive controls.

STUDY DESIGN

A case-control study was performed. Plasma was collected from women with preeclampsia and normotensive controls matched for age, gestational age, and body mass index. Plasma NGAL concentrations were measured by specific enzyme-linked immunosorbent assay.

RESULTS

Patients with preeclampsia had significantly higher NGAL concentrations than controls (median [range]: 203.8 ng/mL [66.1-575.4] vs. 122.8 ng/mL [7.0-669.7]; P = .047). In subgroup analysis, patients with severe preeclampsia had significantly higher NGAL concentrations than those with mild preeclampsia. Plasma NGAL concentrations were positively correlated with the amount of proteinuria in women with preeclampsia (P = .003).

CONCLUSIONS

Plasma NGAL concentrations were significantly elevated in women with preeclampsia versus normotensive controls, and concentrations appear to be associated with the severity of the disease.

Angiogenic factors in preeclampsia and related disorders

During fetal development, the human placenta undergoes high levels of both angiogenesis and vasculogenesis. Additionally, the developing placenta undergoes a process of vascular mimicry (referred to as pseudovasculogenesis) as cytotrophoblasts convert from an epithelial to an endothelial phenotype. The initiation, maturation, and maintenance of the placental vasculature are of critical importance. Failure to do so can lead to adverse obstetric outcomes such as preeclampsia and/or intrauterine growth restriction (IUGR). Furthermore, the foundation of many aspects of adult health is laid in utero. In this context, normal placental function is not only critical for normal fetal development but can also permanently influence long-term health and disease. Understanding the mechanisms that regulate placental vasculogenesis and angiogenesis is therefore of critical importance. This chapter will focus on placental vascular development with a particular emphasis on the role of angiogenic factors in the pathogenesis of the maternal syndrome of preeclampsia and related disorders.