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.

Congenital Solitary Functioning Kidney: A Review.

BACKGROUND: Solitary functioning kidney (SFK) is a subgroup of the Congenital Anomalies of the Kidneys and Urinary Tract (CAKUT). Although the prognosis of these patients was considered good in the past, numerous studies have shown different levels of kidney damage associated with this condition. Serum creatinine measurement is still the most used marker to assess renal function, even though the limitations are widely known. OBJECTIVE: The present review aims to summarize and update the scientific literature on congenital SFK, discussing its pathophysiology, diagnosis, complications, prognosis, role of novel urinary biomarkers, treatment, and follow-up. RESULTS: The natural history of congenital SFK is still an unresolved issue due to several factors. Although it has not yet been proven in humans, Brenner's hyperfiltration hypothesis is the most concrete theory to explain the poor renal outcomes of patients born with one functioning kidney. The search for novel urinary biomarkers capable of assessing renal function and predicting renal outcomes has already started, but there are still few studies on this specific population. Among the most studied markers, Cystatin C, EGF and NGAL have shown potential usefulness for the follow-up of these patients. The treatment still relies on the search for kidney injury and general renoprotective measures. CONCLUSION: Further research with a longer follow-up duration is needed to better understand the natural course of congenital SFK and the role of novel urinary biomarkers in this specific population. Thus, it will be possible to improve the prognosis of these patients.