Cystatin C and lipocalin — endogenous markers of glomerular filtration in children born prematurely

The need to search for new markers of the functional state of the kidneys is increasing due to the gain in the number of extremely premature infants. The review analyzes publications on the possibilities of assessing kidney function using cystatin C and lipocalin in children born prematurely. The constant rate of cystatin C production in all tissues, its elimination through the renal glomerular filter, the absence of secretion in the proximal tubules, as well as independence from many factors, including gender, age, diet, inflammation are ideal conditions for its use as an endogenous biochemical marker of glomerular filtration. Due to biochemical features, the analysis of serum levels of cystatin C was established to be a promising method in the diagnosis of acute renal injury (AKI) in premature infants. For a comprehensive assessment of kidney function in premature infants, simultaneous determination of lipocalin and cystatin C levels in the blood may be important. At the same time, the evaluation of these indicators may have diagnostic significance in predicting the development of chronic kidney disease in children who underwent AKI in infancy. The absence of reference values of lipocalin and cystatin C in premature infants was concluded to hinder the clinical use of their quantitative analysis for a comprehensive assessment of the functional state of the kidneys.