New urinary biomarkers of tubular injury in patients with focal segmental glomerulosclerosis

Objective:We explored the relevance of the markers with tubular interstitial lesion and glomerular function in patients with focal segmental glomerulosclerosis (FSGS) in order to find the specific and sensitive biomarkers. Methodology:Sixty patients with biopsy-proved idiopathic FSGS were recruited in this study. Thirty-six idiopathic menbranuous nephropathy (MN) and 30 minimal change diseases (MCD) were regarded as the control groups. The changes of urinary kideny injury molecule-1 (KIM-1), IL-18, neutrophil-gelatinase-associated lipocalin (NGAL), proteinuria, N-acetyl-β-glucosaminidase (NAGase), retinal-binding protein (RBP), Cystatin C (CysC), C3, α2-MG and renal biochemistry were observed in each group and compared. The effects of urinary data, blood biochemistry as well as histological manifestations on the changes of KIM-1, IL-18, NGAL in FSGS patients were evaluated. Results:(1)Under the same proteinuria level, urinary KIM-1, IL-18, NGAL, NAG, RBP, C3,α2-MG were increased in patients with FSGS compared with MN and MCD (P0.05).(2)In FSGS patients, urinary KIM-1 was increased along with serum CysC (P0.05), and the patients with higher urinary NGAL showed proteinuria, BUN, urinary C3 and α2-MG increased (P0.05), but serum total protein and albumin decreased (P0.05).(3)FSGS patients with acute tubular interstitial injury showed KIM-1 and NGAL increased compared with that have only chronic tubular interstitial lesions (P0.05).(4)In 21 patients with normal NAG and RBP, their urinary KIM-1, IL-18, NGAL was also increased, and the acute tubular interstitial lesions were found in histological examinations. Regard to diagnosis acute tubular and interstitial injury, the area under ROC curve of KIM-1, NGAL and NAG were greater than that of IL-18, RBP and CysC. Conclusion:Our study demonstrated the patients with FSGS had serious tubular interstitial damages compared with MN and MCD, and the reason was independent of the quantity of proteinuria. KIM-1, NGAL, NAG are more specific and sensitive novel biomakers than IL-18, RBP and CysC to estimate the acute tubular and interstitial function.