OBJECTIVETo screen the differentially expressed proteins in the urine of children with steroid-sensitive and steroid-resistant minimal change nephrotic syndrome (SRINS and SSINS, respectively).

METHODSUrine samples were collected from 10 children with SRINS and 70 with SSINS as well as 30 healthy volunteers (control). Isoelectric focusing and two-dimensional electrophoresis in combination with matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry was performed for analysis of the urine proteins.

RESULTS AND CONCLUSIONIn the urine samples, 30 protein spots were identified to have differential expression between SRINS and SSINS. Further analysis of 14 protein spots identified 12 proteins expressing in SRINS, namely kinesin family member 27, PITPNB, bullous pemphigoid antigen, alpha-1 protease inhibitor, Zn-alpha-2GP, alpha-1B-glycoprotein, serum albumin precursor, haptoglobin precursor, kinesin like motor protein, IRAK4, cytoplasmic dynein and cytokeratin 9. Nine of these 12 proteins were up-regulated (U1-U3, U5, U7-U9, U11-U12) and 3 down-regulated (D4, D6, D10) in SRINS, suggesting that these proteins may serve as the potential therapeutic targets and as new diagnostic markers for steroid-resistant nephrotic syndrome.