Placental growth factor: as an early second trimester predictive marker for preeclampsia in normal and high-risk pregnancies in a Turkish population

Pathophysiology of Preeclampsia and L-Arginine/L-Citrulline Supplementation as a Potential Strategy to Improve Birth Outcomes

In preeclampsia, the shallow invasion of cytotrophoblast cells to uterine spiral arteries, leading to a reduction in placental blood flow, is associated with an imbalance of proangiogenic/antiangiogenic factors to impaired nitric oxide (NO) production. Proangiogenic factors, such as vascular endothelial growth factor (VEGF) and placental growth factor (PlGF), require NO to induce angiogenesis through antioxidant regulation mechanisms. At the same time, there are increases in antiangiogenic factors in preeclampsia, such as soluble fms-like tyrosine kinase type 1 receptor (sFIt1) and toll-like receptor 9 (TLR9), which are mechanism derivates in the reduction of NO bioavailability and oxidative stress in placenta.Different strategies have been proposed to prevent or alleviate the detrimental effects of preeclampsia. However, the only intervention to avoid the severe consequences of the disease is the interruption of pregnancy. In this scenario, different approaches have been analysed to treat preeclamptic pregnant women safely. The supplementation with amino acids is one of them, especially those associated with NO synthesis. In this review, we discuss emerging concepts in the pathogenesis of preeclampsia to highlight L-arginine and L-citrulline supplementation as potential strategies to improve birth outcomes. Clinical and experimental data concerning L-arginine and L-citrulline supplementation have shown benefits in improving NO availability in the placenta and uterine-placental circulation, prolonging pregnancy in patients with gestational hypertension and decreasing maternal blood pressure.

Analysis of serum placental growth factor levels in preeclamptic and normotensive pregnant women in Lagos, Nigeria: a worthwhile screening tool?

The clinical usefulness of serum placental growth factor (PlGF) as a predictive biomarker of preeclampsia is currently being examined. However, there are still conflicting results in the literature. We assessed the association between maternal low PlGF levels and the occurrence and severity of preeclampsia. This was an analytical cross-sectional study conducted among 60 women with preeclampsia, and an equal number of matched normotensive pregnant women. PlGF concentrations were analysed using the ELISA method. Bivariate and multivariate analysis was used to test for the association between low maternal PlGF levels and the occurrence of preeclampsia and its severity. Statistical significance was reported at p < .05. The study showed that having a low maternal PlGF level (Adjusted OR 14.23; 95%CI 8.06, 29.71) together with being primigravid (Adjusted OR 3.97; 95%CI 1.03, 6.18) and having an unbooked pregnancy (Adjusted OR 8.07; 95%CI 2.06, 19.40) were independently associated with preeclampsia. We established an association between low maternal PlGF levels and preeclampsia, but no similar association with severe preeclampsia. The use of PlGF as a potential predictive marker and a reliable screening tool may have a profound implication on the prevention of preeclampsia and the subsequent reduction in its associated morbidity and mortality.Impact statementWhat is already known on this subject? The utility of serum placental growth factor (PlGF) as a predictive biomarker of preeclampsia is currently being examined, however, there are conflicting results of its clinical usefulness in the literature.What do the results of this study add? This study that assessed the association between maternal low PlGF levels and the occurrence and severity of preeclampsia showed that having a low maternal PlGF level together with being primigravid and having an unbooked pregnancy were independently associated with the occurrence of preeclampsia. However, we were unable to establish any significant relationship between maternal PlGF and the severity of preeclampsia.What are the implications of these findings for clinical practice and/or further research? We opined that the use of PlGF as a potential predictive marker and a reliable screening tool may have a profound clinical implication on the prevention and reduction in the associated morbidity and mortality of preeclampsia. However, there is an urgent need for more robust longitudinal studies to define the regulation of placental vascular development and the clinical usefulness of maternal serum PlGF and other placental biomarkers as potential screening tools for preeclampsia among black African women.

Placental Tissues as Biomaterials in Regenerative Medicine

Placental tissues encompass all the tissues which support fetal development, including the placenta, placental membrane, umbilical cord, and amniotic fluid. Since the 1990s there has been renewed interest in the use of these tissues as a raw material for regenerative medicine applications. Placental tissues have been extensively studied for their potential contribution to tissue repair applications. Studies have attributed their efficacy in augmenting the healing process to the extracellular matrix scaffolds rich in collagens, glycosaminoglycans, and proteoglycans, as well as the presence of cytokines within the tissues that have been shown to stimulate re-epithelialization, promote angiogenesis, and aid in the reduction of inflammation and scarring. The compositions and properties of all birth tissues give them the potential to be valuable biomaterials for the development of new regenerative therapies. Herein, the development and compositions of each of these tissues are reviewed, with focus on the structural and signaling components that are relevant to medical applications. This review also explores current configurations and recent innovations in the use of placental tissues as biomaterials in regenerative medicine.

Longitudinal changes in placental biomarkers in women with early versus late placental dysfunction

Objective: To evaluate longitudinal changes of angiogenic biomarkers in early- (EO-PD) versus late-onset (LO-PD) placental dysfunction. Methods: Serum PlGF and sFlt-1 measured at different intervals in EO-PD (n= 43), LO-PD (n= 31) and controls (n = 133). Results: sFlt-1/PlGF ratio was higher at 16 weeks (30.6 vs 17.5), 20 weeks (29.3 vs 8.9) and 30 weeks (16.6 vs 6.7) in EO-PD vs controls (all p< 0.05), but not in LO-PD. Longitudinal changes for all intervals had higher AUC than single measurements. Conclusion: Longitudinal biomarker change between 12 and 30 weeks could improve prediction of EO-PD compared to single measurements.

Predictive Performance of PlGF (Placental Growth Factor) for Screening Preeclampsia in Asymptomatic Women: A Systematic Review and Meta-Analysis

Preeclampsia is a systemic syndrome that seems to originate from the placenta and is associated with an imbalance between angiogenic factors in the maternal circulation. One of the well-studied and widely used factors is PlGF (placental growth factor), the levels of which drop in women destined to develop preeclampsia. This drop is known to precede the development of actual signs and symptoms of preeclampsia, thus proving to be a useful screening tool in predicting the disease. The literature varies widely in terms of the clinical usefulness of the test. We conducted a meta-analysis to study the predictive accuracy of PlGF in asymptomatic women. Our analysis included 40 studies with 3189 cases of preeclampsia and 89 498 controls. The overall predictive odds ratio of the test was 9 (6-13). Subgroup analysis evaluating various PlGF thresholds demonstrated that the predictive values were highest for PlGF levels between 80 and 120 pg/mL with a high predictive odds ratio of 25 (7-88), a sensitivity of 0.78 (95% CI, 0.67-0.86), a specificity of 0.88 (95% CI, 0.75-0.95), a positive likelihood ratio of 6.3 (95% CI, 2.7-14.7), and a negative likelihood ratio of 0.26 (95% CI, 0.16-0.42). Additionally, the accuracy was higher when the test was performed after 14 weeks of gestation (OR, 10 [7-15]) and for prediction of early onset preeclampsia (OR, 18 [9-37]). We conclude that PlGF is a useful screening tool to predict preeclampsia. Nonetheless, its utility should be judged with caution and randomized controlled trials are warranted to explore if its implementation improves perinatal outcomes in asymptomatic women.

Influences of placental growth factor on mouse retinal vascular development

BACKGROUND

Placental growth factor (PGF) is important for wound-healing and vascular collaterogenesis. PGF deficiency is associated with preeclampsia, a hypertensive disease of human pregnancy. Offspring born to preeclamptic mothers display cognitive impairments and brain vascular and neurostructural deviations. Low PGF production during development may contribute to alterations in offspring cerebrovascular beds. Retina is a readily accessible part of the central nervous system with a well-described pattern of vascular development in mice. Impacts of PGF deficiency were addressed during mouse retinal vascularization.

RESULTS

Retinal vessels were compared between Pgf^-/- and congenic C57BL/6 (B6) mice. PGF deficiency altered neonatal retinal vascularization patterns. Some anatomic alterations persisted into adulthood, particularly in males. Greater arterial wall collagen IV expression was found in adult Pgf^-/- females. Pregnancy (studied in adult females at gestational days 11.5 or 18.5) induced subtle changes upon the mother's retinal vasculature but these pregnancy-induced changes did not differ between genotypes. Significant sex-related differences occurred between adult male and female B6 although sexually dimorphic retinal vascular differences were absent in B6 neonates.

CONCLUSIONS

Overall, PGF has a role in retinal vascular angiogenesis and vessel organization during development but does not affect retinal vessel adaptations in adult females during pregnancy. Developmental Dynamics 246:700-712, 2017. © 2017 Wiley Periodicals, Inc.

Serum VEGF and PGF may be significant markers in prediction of severity of preeclampsia

OBJECTIVE

The aim of this study evaluate the value of vascular endothelial growth factor (VEGF) and placental growth factor (PGF) serum levels in prediction of preeclampsia, severity and onset time of the disease.

METHODS

Twenty five placentas of pregnant women diagnosed with preeclampsia (15 severe preeclampsia, 10 mild preeclampsia) and peripheral venous blood samples were collected. The placental and serum levels of VEGF and PGF were measured.

RESULTS

VEGF level was significantly higher in cases and the optimal cut-off point was calculated as 600.5 to differentiate the cases and the controls, with 64% sensitivity and 100% specificity. There was a significant increase in median serum level of VEGF in severe cases compared to the mild cases and the controls. The optimal cut-off point for VEGF was calculated as 673.5 to differentiate mild and severe cases, with 93.3% sensitivity and 90% specificity. Whereas, PGF was significantly lower in severe cases than that in the mild cases and controls. The optimal cut-off point for PGF was calculated as 16.1 to differentiate mild and severe cases, with 66.7% sensitivity and 100% specificity.

CONCLUSION

VEGF and PGF may be significant markers in prediction of severity of preeclampsia, and VEGF may also be valuable in prediction of preeclampsia.