Neutrophil gelatinase-associated lipocalin and Cathepsin L as early predictors of kidney dysfunction in children with type 1 diabetes

The aim of this study was to evaluate serum levels and urinary excretion of neutrophil-gelatinase associated lipocalin (respectively sNGAL and uNGAL) and urinary excretion of Cathepsin L (uCathL) in children with type 1 diabetes mellitus (DM1) who presented normoalbuminuria and the estimated glomerular filtration rate (eGFR) above 90 mL/min/1.73 m2.The study group consisted of 63 children with a diabetes duration of 5.16 ± 3.39 years. The degree of albuminuria was based on urine albumin-to-creatinine ratio (ACR), while eGFR was based on serum cystatin C. Glomerular hyperfiltration (GH) was defined as an eGFR value above 135 mL/min/1.73 m2.Children with DM1 showed significantly higher concentrations of uNGAL, and lower sNGAL and uCathL. Significant changes of uNGAL and uCathL levels were even found in children without GH and with optimal glycaemic control (HbA1c7.5%). Positive correlations between uNGAL, ACR and eGFR were shown, as well as between uCathL and eGFR.Significant changes in the concentration of markers of early kidney injury: sNGAL, uNGAL, and uCathL, can occur in children with DM1 and normoalbuminuria. The changes of uNGAL and uCathL can be even found in children without GH and with optimal glycaemic control. The earliest signs of diabetic kidney dysfunction seem to result from tubular damage.