Abstract:

Objective To study the correlation of urinary neutrophil gelatinase-associated lipocalin (NGAL) with chronic kidney disease (CKD) renal tubulointerstitial injury. Methods A total of 30 healthy subjects (healthy control group) and 124 patients with CKD undergoing renal biopsy were enrolled. Serum cystatin C (Cys C), urinary NGAL, urinary retinol binding protein (RBP) and urinary beta2-microglobulin (β2-MG) were determined. Correlation analysis was carried out on urinary NGAL with serum Cys C, urinary RBP and urinary β2-MG. According to the degrees of renal biopsy results, renal tubulointerstitial injury was classified into mild injury, mild to moderate injury, moderate injury and severe injury groups. By Spearman rank, the correlation of urinary NGAL with CKD renal tubulointerstitial injury was analyzed. The performance of urinary NGAL for the diagnosis of CKD renal tubulointerstitial injury was analyzed by receiver operating characteristic (ROC) curve. Results The urinary NGAL of CKD groups was significantly higher than that of control group (P=0.000). With the increasing of CKD renal tubulointerstitial injury, urinary NGAL increased gradually, and the differences were statistically significant (P<0.05). The urinary NGAL was positively correlated with urinary RBP, urinary β2-MG and serum Cys C (r=0.784, 0.692 and 0.759, P<0.01). There was positive correlation between urinary NGAL and renal tubulointerstitial injury (r=0.762, P<0.01). The area under ROC curve was 0.855, and the optimal cut-off point was 45.35 ng/mL. The sensitivity was 77.2%, and the specificity was 84.6%. Conclusions Urinary NGAL contributes to the diagnosis, treatment and prognosis of CKD renal tubulointerstitial injury, which is a novel biomarker for the disease.

Key words: Neutrophil gelatinase-associated lipocalin, Chronic kidney disease, Renal tubulointerstitial, Injury