Avaliação dos níveis urinários e no líquido amniótico da proteína Uromodulina e sua correlação com outros parâmetros bioquímicos de função renal fetal

Abstract

Obstructive nephropathys are a heterogeneous group of diseases that affect the fetus. Early diagnosis of morphology and renal function is very important because it allow establish the level and severity of the injury and treatment that could be: monitoring Reference Center, intrauterine treatment (alternative for survival and preservation of renal function) or anticipation of delivery. Therapeutic success depends on the adequade selection of fetuses for each procedure. Among the good prognostic factors, gestational age (1st and 2nd trimester) and the absence of associated malformations stand out. However, the current criteria used in the evaluation of renal function do not have the desired accuracy. Therefore, the dosage of biochemical markers in fetal urine or amniotic fluid are useful in conjunction with ultrasound and evaluation of amniotic fluid volume in the prediction of renal function of the fetus during the prenatal period. A new protein may contribute to the diagnosis of obstructive uropathy. Uromodulin is produced only in the kidney and in normal conditions the protein is secreted in larger amounts in human urine. Its functions are still unknown but there are evidences that this protein helps ion transport processes and waterproofing kidney and also provides defense against urinary tract infections. Recently, some mutations in this protein showed a role in genetic diseases and also, good results on detection of chronic kidney disease (CKD) in adults. Given the need to predict the kidney function of the fetus before birth to set up therapeutic in each case and the controversial results obtained through analysis of biochemical parameters already used, the study of uromodulin in samples of urine and fetal amniotic fluid may present a new possible biomarker of fetal kidney function. Objectives: Evaluate if the uromodulin protein is produced during fetal life and eliminated by the kidneys, through quantitative analysis of this protein in fetal urine and amniotic fluid and to compare the dosage of uromodulin with other biochemical parameters already used. Methods: From March 2013 to March 2015, 29 pregnant women were selected whose fetuses were followed up at the Fetal Medicine Center of Clinical Hospital (CEMEFE / HC) and had the indication of invasive tests for fetal diagnosis. The assay was made by ELISA using the kit BioVendor Human Uromodulin (RD19116320R). Results: The samples submitted to test were read and assayed by absorbance calculation of uromodulin. In fetal urine besides the dosage of uromodulin was held the dosage of osmolality and creatinine and the results were correlated. Uromodulin levels showed moderately correlation with Osmolarity and this correlation was statistically significant. There was no significance with the other parameters analyzed. Moreover, uromodulin showed a tendency to present lower values in fetuses who had renal problems in prenatal care. Conclusion: The analysis of uromodulin proved that is possible and measurable in fetal urine and amniotic fluid samples on fetuses who carries or noncarriers obstructive uropathy.