Urinary sFlt-1 and PlGF levels are strongly correlated to serum sFlt-1/PlGF ratio and serum PlGF in women with 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.

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.