Urinary biomarkers as early indicators of acute kidney injury in neonates with perinatal asphyxia

<p>Perinatal asphyxia (PA) is a condition in which there is a decreased or interrupted blood and oxygen supply to the tissues of the fetus, i.e., the newborn, immediately before, during, or immediately after delivery. It constitutes a significant cause of mortality, accounting for 23-24% of all neonatal deaths. The estimated global incidence of perinatal hypoxia is approximately 0.5% of the total number of live births at gestational age over 36 weeks. PA negatively impacts the entire organism, especially metabolically demanding tissues. Due to the sensitivity of the kidneys to oxygen deprivation, acute kidney injury (AKI) can develop within the first 24 hours of the ischemic episode. Prolonged ischemia may lead to irreversible cortical necrosis. Early recognition of AKI is crucial for adequate fluid and electrolyte replacement, as the action of pre-renal etiological factors is a dynamic process with a reversible onset. However, AKI represents a poor prognostic sign, with higher mortality in neonates who develop AKI after perinatal asphyxia, and up to 40% of survivors may have permanent kidney damage. Given the specificity of both the population and the clinical entity, there is a clear need for newer, more sensitive, and specific biomarkers of renal function. The aim of the paper was to review the most significant urinary biomarkers in neonates with perinatal asphyxia that could be crucial for early detection of renal impairment. Analysis of scientific and professional papers published in the last ten years in international scientific and professional journals available in the PubMed database. When considering a potential biochemical marker, the type of biological sample in which it is quantified is a crucial characteristic that must be taken into account. For newborns, obtaining a sample non-invasively is of utmost importance. In this context, urine analysis emerges as a good choice. Metabolites in the urine of PA patients have been proven significant for monitoring the renal function. Unfortunately, urine as a biological sample has the drawback that it cannot be obtained immediately after birth, and a significant number of neonates due to pre-existing renal damage may be anuric.</p>