Avaliação longitudinal de marcadores urinários de função renal glomerular e tubular em recém-nascidos prematuros saudáveis

Abstract

Introduction: The most used endogenous marker of renal function in clinical practice is serum creatinine concentration. However, especially for neonates, serum levels of creatinine are quite variable and suffer interference by the immature kidney and maternal creatinine concentration. In this context, the search for novel biomarkers is an important scientific goal, mainly for preterm neonates. Therefore, the aim of this study was to measure markers of glomerular and tubular function in healthy preterm neonates at 72 hours and 3 weeks of life. Patients and Methods: Urine samples were collected in 40 preterm neonates with 28 to 34 incomplete weeks of gestational age. None of the participants had comorbidities, malformations and infections. The samples were collected at 72 hours of life and at 3 weeks after birth. Measurements of Calbindin, Collagen IV, FABP1, GSTα, IP-10, KIM-1, Osteoactivin, Renin, TFF-3, TIMP-1, α-1-Microglobulin, Albumin, Clusterin, Cystatin C, EGF, Lipocalin-2/NGAL and Osteopontin were performed using panels 1 and 2 of multiplex kits of kidney injury. Data were analyzed using the software GraphPad Prism version 6.0. Results: The preterm neonates included 55% of males with gestational age of 301 weeks and birth weight of 1477428 grams. The most frequent maternal condition associated with preterm birth was preeclampsia (80%). Molecules related to glomerular function (albumin, EGF, clusterin, microglobulin and osteopontin) showed a significant increase in the concentrations obtained at 3 weeks of life compared to 72 hours of life. On the other hand, cystatin C did not change. Markers related to tubular injury (KIM-1 and NGAL) remained also unchanged at 72 hours and 3 weeks after birth. Conclusion: The elevation of molecules related to glomerular function indicates an intense increase of glomerular filtration rate from 72 hours until 3 weeks of life, which was not detected with the measurement of cystatin C.