Usefulness of urinary kidney injury molecule-1 (KIM-1) in children with idiopathic nephrotic syndrome treated with cyclosporine A

Background. Some forms of idiopathic nephrotic syndrome (INS ) are treated with cyclosporine A (CsA) as an alternative method. A serious adverse effect of the drug is nephrotoxicity. To help optimize the therapy, researchers are looking for early kidney injury markers.

Objectives. To determine KI M-1 (kidney injury molecule-1) plasma and urine concentrations in children with INS and to evaluate the suitability of the protein as CsA nephrotoxicity marker.

Material and methods. 30 children with steroid-dependent (SDNS ) and steroid-resistant (SRNS ) INS and 22 healthy children were enrolled to the study. KI M-1 plasma and urine concentrations were determined in children with INS before the administration of CsA, and then after 6 and 12 months, using the enzyme-linked immunosorbent assay (ELISA ).

Results. In the INS group, higher KI M-1 plasma and urine concentration were observed prior to the administration of CsA compared to the reference group. During the follow-up period, KI M-1 plasma levels were increasing, and the values varied significantly at all time points. KI M-1 urine levels after 6 and 12 months of therapy were significantly higher compared to baseline, and statistically, did not vary significantly when determined between 6 and 12 months of treatment. No correlation was found between KI M-1 urine concentrations and CsA blood levels, proteinuria or eGFR. The parameters analysed in plasma and urine of SDNS and SRNS diagnosed patients, did not vary significantly.

Conclusions. Urine KI M-1 concentration were found to vary in INS children treated with CsA, which suggests that the protein may be suitable for monitoring these patients.