sFlt-1, PlGF, sFlt-1/PlGF ratio and uterine artery Doppler for preeclampsia diagnostics

A prospective and comparative investigation of blood sFlt-1, P1GF, and niacin concentrations in women with premature ovarian insufficiency

OBJECTIVE

Endothelial dysfunction is an important component of preeclampsia like premature ovarian insufficiency (POI), and it is reported that placental growth factor (P1GF) and soluble fms-like tyrosine kinase receptor-1 (sFlt-1) levels are important in preeclampsia. Extra-placental sources for P1GF and sFlt-1 have also been identified, including various cell types. In animal models of POI, niacin treatment inhibited follicular apoptosis under hazardous conditions while significantly reducing cumulus cell apoptosis. The number of developing follicles also increased after niacin was given. This study was designed to determine blood sFlt-1, P1GF, and niacin concentrations in women with idiopathic POI (iPOI) compared with those of healthy women.

METHODS

The study comprised 45 women with iPOI and 45 healthy women. Blood was obtained and analyzed at the early follicular phase of the menstrual cycle and sFlt-1, P1GF, and niacin levels were measured using a commercially available enzyme-linked immunosorbent assay kit.

RESULTS

No significant differences were observed in the two groups according to the gravidity numbers, parity, abortion, live births, and menarche ages (p ≥ 0.05). In the iPOI group, the mean anti-mullerian hormone value was 0.03 ± 0.04 (min-max, 0.00-0.21) ng/ml. sFlt-1, P1GF, niacin levels, and also the sFlt-1/P1GF ratio were lower in the iPOI group (p < 0.01). A significant discriminative role of sFlt-1, P1GF, niacin levels, and the sFlt-1/P1GF ratio for the presence of iPOI, with cut-off values of 5.13, 10.28, 37.17, and 0.61 ng/ml, respectively, were reported in the receiver operating characteristics curve analysis.

CONCLUSIONS

Lower levels of P1GF, sFlt-1, niacin, and sFlt-1/P1GF ratios may be associated with the development of POI/iPOI. Further studies are required to better understand the etiopathogenesis of POI/iPOI.

CLINICAL TRIAL NUMBER

NCT04641624 (clinicaltrials.gov).

PIGF and Flt-1 on the surface of macrophages induces the production of TGF-β1 by polarized tumor-associated macrophages to promote lung cancer angiogenesis

BACKGROUND

The interaction between tumor cells and tumor microenvironment is a necessary condition for promoting the metastasis of malignant tumors.

METHODS

Two different transwell culture systems were interfered with by recombinant factor placental growth factor (re-PIGF) and the re-PIGF + transforming growth factor-β1 (TGF-β1)-neutralizing antibody (anti-TGF-β1). We performed immunofluorescence, flow cytometry and enzyme linked immunosorbent assay (ELISA) to analyze the expression of PIGF, fms-like tyrosine kinase-1 (Flt-1), macrophage marker F4/80 ⁺, macrophage M2 marker CD163⁺ and TGF-β1 in vitro. Meanwhile, cell viability assay and optical microscope assay were conducted to explore the cell viability and vascularization ability of human umbilical vein endothelial cells (HUVECs).

RESULTS

Re-PIGF increased the expression of PIGF in A549 cells and the expression of Flt-1 in BM-Mac cells, and significantly enhanced the ability of bone marrow-derived macrophages (BM-Mac) to transform into macrophages. At the same time, re-PIGF increased the expression of cytokine TGF-β1 in A549 cells/BM-Mac transwell culture system. On the contrary, re-PIGF + anti-TGF-β1 inhibited the expression of Flt-1 in BM-Mac cells and inhibited the ability of BM-Mac cells to transform into macrophages. Finally, re-PIGF + anti-TGF-β1 reduced the cell viability and angiogenesis of HUVECs.

CONCLUSION

The surface molecule PIGF of lung cancer cells could bind to the receptor Flt-1 on the surface of macrophages, thereby increasing the production of TGF-β1, and ultimately promoting the formation of angiogenesis in lung cancer.

Stimulation of soluble guanylate cyclase diminishes intrauterine growth restriction in a rat model of placental ischemia

Placental ischemia in preeclampsia (PE) results in hypertension and intrauterine growth restriction (IUGR). Stimulation of soluble guanylate cyclase (sGC) reduces blood pressure in the clinically relevant reduced uterine perfusion pressure (RUPP) rat model of PE, implicating involvement in RUPP-induced hypertension. However, the contribution of sGC in the development of IUGR in PE is not known. Thus, this study demonstrated the efficacy of Riociguat, an sGC stimulator, in IUGR reversion in the RUPP rat model of PE, and tested the hypothesis that improvement in fetal weight occurs in association with improvement in placental perfusion, placental morphology, and placental nutrient transport protein expression. Sham or RUPP surgery was performed at gestational day 14 (G14) with administration of vehicle (Sham or RUPP) or the sGC stimulator (Riociguat, 10 mg/kg/day sc; sGC-treated) until G20. Fetal weight was reduced (P = 0.004) at G20 in RUPP but not in sGC-treated RUPP compared with Sham, the control group. At G20, uterine artery resistance index (UARI) was increased (P = 0.010) in RUPP, indicating poor placental perfusion; proportional junctional zone surface area was elevated (P = 0.035), indicating impaired placental development. These effects were ameliorated in sGC-treated RUPP. Placental protein expression of nutrient transporter heart fatty acid-binding protein (hFABP) was increased (P = 0.008) in RUPP but not in sGC-treated RUPP, suggesting a compensatory mechanism to maintain normal neurodevelopment. Yet, UARI (P < 0.001), proportional junctional zone surface area (P = 0.013), and placental hFABP protein expression (P = 0.008) were increased in sGC-treated Sham, suggesting a potential adverse effect of Riociguat. Collectively, these results suggest sGC contributes to IUGR in PE.

Prediction of Preeclampsia and Intrauterine Growth Restriction: Development of Machine Learning Models on a Prospective Cohort

BACKGROUND

Preeclampsia and intrauterine growth restriction are placental dysfunction-related disorders (PDDs) that require a referral decision be made within a certain time period. An appropriate prediction model should be developed for these diseases. However, previous models did not demonstrate robust performances and/or they were developed from datasets with highly imbalanced classes.

OBJECTIVE

In this study, we developed a predictive model of PDDs by machine learning that uses features at 24-37 weeks' gestation, including maternal characteristics, uterine artery (UtA) Doppler measures, soluble fms-like tyrosine kinase receptor-1 (sFlt-1), and placental growth factor (PlGF).

METHODS

A public dataset was taken from a prospective cohort study that included pregnant women with PDDs (66/95, 69%) and a control group (29/95, 31%). Preliminary selection of features was based on a statistical analysis using SAS 9.4 (SAS Institute). We used Weka (Waikato Environment for Knowledge Analysis) 3.8.3 (The University of Waikato, Hamilton, NZ) to automatically select the best model using its optimization algorithm. We also manually selected the best of 23 white-box models. Models, including those from recent studies, were also compared by interval estimation of evaluation metrics. We used the Matthew correlation coefficient (MCC) as the main metric. It is not overoptimistic to evaluate the performance of a prediction model developed from a dataset with a class imbalance. Repeated 10-fold cross-validation was applied.

RESULTS

The classification via regression model was chosen as the best model. Our model had a robust MCC (.93, 95% CI .87-1.00, vs .64, 95% CI .57-.71) and specificity (100%, 95% CI 100-100, vs 90%, 95% CI 90-90) compared to each metric of the best models from recent studies. The sensitivity of this model was not inferior (95%, 95% CI 91-100, vs 100%, 95% CI 92-100). The area under the receiver operating characteristic curve was also competitive (0.970, 95% CI 0.966-0.974, vs 0.987, 95% CI 0.980-0.994). Features in the best model were maternal weight, BMI, pulsatility index of the UtA, sFlt-1, and PlGF. The most important feature was the sFlt-1/PlGF ratio. This model used an M5P algorithm consisting of a decision tree and four linear models with different thresholds. Our study was also better than the best ones among recent studies in terms of the class balance and the size of the case class (66/95, 69%, vs 27/239, 11.3%).

CONCLUSIONS

Our model had a robust predictive performance. It was also developed to deal with the problem of a class imbalance. In the context of clinical management, this model may improve maternal mortality and neonatal morbidity and reduce health care costs.

Preeclampsia – Prediction and Monitoring Factors

Preeclampsia is one of the leading causes of maternal and perinatal morbidity and mortality, usually characterized by hypertension and proteinuria. Despite high incidence of preeclampsia the pathophysiological basis of preeclampsia is still not clear and there are a number of mechanisms and signaling pathways that intertwine. It is very important to develop specific and reliable predictive algorithms in order to enable early initiation of therapy due to facts that incidence of preeclampsia has upward trend and that cause adverse maternal and fetal outcome. Some of the most commonly used methods for prediction of preeclampsia include uterine artery Doppler velocimetry, determination of some microRNA, such as miR-210, and assessment of various pro-angiogenic and anti-angiogenic factors from blood. Angiogenic factors that possibly have most important role in pathogenesis of preeclampsia are vascular endothelial growth factor (VEGF) and placental growth factor (PlGF), which promote angiogenesis, and soluble fms-like tyrosine kinase-1 (sFlt1) and soluble form of endoglin (s-Eng), which exhibit anti-angiogenic properties. Aggravating circumstance is that preeclampsia has heterogeneous origin, and due to this fact, the value of individual markers can vary significantly. There is a constant tendency for creating comprehensive algorithm for prediction of preeclampsia which would be sufficiently specific and sensitive, and in the same time cheap and available. In that sense, new clinical studies are needed to show the most effective combination of parameters in the predeclampsia prediction.

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.

Angiogenic factors and the risk of preeclampsia: A systematic review and meta-analysis

Background

The etiological nature of preeclampsia is heterogeneous. The use of biomarkers indices in early pregnancy helps to have appropriate stratification of pregnancies into high- and low risk for the purpose of choosing timely interventions.

Objective

The aim of this systematic review was to determine the pathogenic role of soluble soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) in the prediction of preeclampsia in women.

Materials and Methods

We performed a systematic search of the international databases including PubMed, Scopus, and Web of Science until August 2017. The quality of included studies was assessed using the Newcastle-Ottawa Scale. The primary outcome in this review was preeclampsia. The statistical heterogeneity was assessed using the X2 test and quantified by I2. Pooled effects size was obtained by random effects model. Subgroup analyses were also carried out.

Results

Totally, 284 records were identified in the initial search and 15 records were finally included in the meta-analysis. The pooled odds ratios (ORs) for the association between the high level of sFlt-1 and low level of PlGF and subsequent development of preeclampsia among women were 5.20 (95% CI: 1.24–9.16) and 2.53 (95% CI: 1.33–3.75), respectively. The mean difference for sFlt-1 and PlGF in women with preeclampsia compared to controls was 1.15 (95% CI: 0.43–1.86) and –0.94 (95% CI: –1.37–0.52), respectively.

Conclusion

According to the results from this meta-analysis, increased levels of sFlt-1 and reduced levels of PlGF predict the subsequent development of preeclampsia.

Gestational Hypoxia and Developmental Plasticity

Hypoxia is one of the most common and severe challenges to the maintenance of homeostasis. Oxygen sensing is a property of all tissues, and the response to hypoxia is multidimensional involving complicated intracellular networks concerned with the transduction of hypoxia-induced responses. Of all the stresses to which the fetus and newborn infant are subjected, perhaps the most important and clinically relevant is that of hypoxia. Hypoxia during gestation impacts both the mother and fetal development through interactions with an individual's genetic traits acquired over multiple generations by natural selection and changes in gene expression patterns by altering the epigenetic code. Changes in the epigenome determine "genomic plasticity," i.e., the ability of genes to be differentially expressed according to environmental cues. The genomic plasticity defined by epigenomic mechanisms including DNA methylation, histone modifications, and noncoding RNAs during development is the mechanistic substrate for phenotypic programming that determines physiological response and risk for healthy or deleterious outcomes. This review explores the impact of gestational hypoxia on maternal health and fetal development, and epigenetic mechanisms of developmental plasticity with emphasis on the uteroplacental circulation, heart development, cerebral circulation, pulmonary development, and the hypothalamic-pituitary-adrenal axis and adipose tissue. The complex molecular and epigenetic interactions that may impact an individual's physiology and developmental programming of health and disease later in life are discussed.

Early pregnancy protein multiplex screening reflects circulating and urinary divergences associated with the development of preeclampsia

BACKGROUND

Preeclampsia, a pregnancy disorder characterized by hypertension and proteinuria, represents the leading cause of fetal and maternal morbidity and mortality in developing countries. The identification of novel and accurate biomarkers that are predictive of preeclampsia is necessary to improve the prognosis of patients with preeclampsia.

OBJECTIVE

To evaluate the preeclampsia predictive value of 34 angiogenic-related proteins.

METHODS

We performed a nested cohort case-control study of pregnant women. The profile of the 34 proteins was evaluated at 12, 16, and 20 gestational weeks (GWs), using urine/plasma from 16 women who developed preeclampsia and 20 normotensive pregnant controls by Bio-Plex Pro^TM Human Cancer Biomarker Panels 1 and 2.

RESULTS

The urine concentration of soluble epidermal growth factor receptor (sEGFR), hepatocyte growth factor (HGF), angiopoietin-2 (ANG-2), endoglin (ENG), soluble fas ligand (sFASL), interleukin 6 (IL-6), placental growth factor (PLGF), and vascular endothelial growth factor A (VEGF-A) at 12 GW, prolactin (PRL), ANG-2, transforming growth factor alpha (TGF-α), and VEGF-A at 16 GW, and soluble IL-6 receptor alpha (sIL-6Rα), ANG-2 and sFASL at 20 GW, were different between groups (p < 0.05). The concentration cut-off values calculated in this study for the mentioned proteins, predicted an increased risk to developing preeclampsia in a range of 3.8-29.8 times in the study population.

CONCLUSION

The proteins sEGFR, HGF, ANG-2, sFASL, IL-6, PLGF, VEGF-A, PRL, TGF-α FGF-b, sHER2/Neu sIL-6Rα, ENG, uPA, and insulin-like growth factor binding protein 1 (IGFBP-1), were predictive of the development of preeclampsia and their use as markers for this disease should be considered.

A study of the association between the sFlt-1/PIGF ratio and preeclampsia in Xinjiang Uygur Autonomous Region of China

AIM

It was previously reported that the ratio of soluble fms-like tyrosine kinase-1 (sFlt-1) to placental growth factor (PlGF) can predict the clinical onset of preeclampsia. This study seeks to validate the association between ratios of sFlt-1/PlGF with preeclampsia and to identify the contribution of ethnicity across diverse populations of the Xinjiang Uygur Autonomous Region.

METHODS

Pregnant women were classified into those with preeclampsia (n = 136) and healthy controls (n = 350). Serum levels of sFlt-1 and PlGF were quantified using a Roche serum instrument in both patients and controls.

RESULTS

Compared to healthy controls, women with preeclampsia had significantly higher levels of sFlt-1 (7303.81 pg/ml vs. 2508.69 pg/ml, p < .001) and ratios of sFlt-1/PlGF (241.68 vs. 14.29, p < .001), whereas levels of PIGF were decreased (241.68 vs. 14.29, p < .001). These three values varied greatly across nationalities, and non-Han Chinese subjects (including Uygur, Kazak, Hui) were more likely to experience severe preeclampsia than Han Chinese subjects.

CONCLUSIONS

This is the first study to demonstrate that the ratio of sFlt-1/PlGF can both predict and serve as a diagnostic factor for preeclampsia in pregnant women from different populations within the Xinjiang region of China.