New biomarkers of kidney damage and their use in minimally invasive treatment of urolithiasis

Introduction. The effect of various minimally invasive treatment for kidney stones on renal function has not been sufficiently studied. To assess the specificity, severity, and prognostic significance of renal injury of urolithiasis and its minimally invasive treatment, it is necessary to search for «biomarkers of injury». The concentration of serum urea and creatinine used in routine clinical practice, the glomerular filtration rate change in the later stages of the disease and are functional parameters. Materials and methods. The data were searched in the PubMed, Web of Science, Google Scholar, eLibrary.ru using the following keywords: «acute kidney injury», «KIM-1», «kidney injury molecule 1», «NGAL», «neutrophil gelatinase- associated lipocalin», «L-FABP», «liver-type fatty acid binding protein», «cystatin C», «retrograde intrarenal surgery», «percutaneous nephrolithotomy», «kidney injury urolithiasis», «kidney injury nephrolithiasis». Results. Today new biomarkers have been proposed to detect renal injury at the initial stages. These are neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, kidney injury molecule-1 (KIM-1) and liver-type fatty acid binding protein (L-FABP). The level of NGAL and KIM-1 increases until the serum creatinine level increases and the corresponding histological changes in the renal parenchyma develop. In percutaneous nephrolithotomy, multiple punctures and postoperative bleeding are independent risk factors for deterioration of renal function in the long term, and the large size and high density of stones, staghorn stones, and long duration of intervention are largely associated with the development of acute renal injury in the early postoperative period. Obstructive uropathy affects kidney damage in the postoperative period. The elimination of obstruction leads to a decrease in KIM-1 in urine already in the early postoperative period. The dynamics of biomarker levels suggests that percutaneous nephrolithotomy causes more renal injury than retrograde intrarenal surgery (RIRS). Conclusion. Any minimally invasive treatment for kidney stones may lead to renal injury, which is not always accompanied by impaired function. The mechanisms of renal injury in various variants of minimally invasive treatment for kidney stones have specific features, and the short-term and long-term consequences are currently not fully determined. Further research evaluating the effect of various minimally invasive methods of urolithiasis treatment on the condition of the renal tubules using modern biomarkers is needed.