Neutrophil Gelatinase-Associated Lipocalin in Dialyzed Patients Is Related to Residual Renal Function, Type of Renal Replacement Therapy and Inflammation

Abstract

Neutrophil gelatinase-associated lipocalin (NGAL) has recently been proved useful in the quantitation of chronic kidney disease. A cross-sectional study was performed to assess NGAL in serum, urine and ultrafiltrate in relation to the type of renal replacement therapy and NGAL correlations with renal function and markers of inflammation. Methods: NGAL, hsCRP, TNFα, and IL-6 were measured using commercially available kits in 200 patients on hemodialysis (HD), 17 on hemodiafiltration (HDF). Results: Patients on HDF had lower serum NGAL than those on HD. In hemodialyzed patients with residual renal function, serum NGAL was significantly lower than in anuric patients. NGAL was significantly higher in patients dialyzed on modified cellulose dialyzers versus polysulphone dialyzers. NGAL correlated with age, residual renal function, hsCRP, IL-6, TNF-α, time on HD, ferritin, TSAT, creatinine, urea, urea reduction ratio, and Kt/V in hemodialyzed patients. In multiple regression analysis, residual renal function and hsCRP were predictors of NGAL in hemodialyzed patients. NGAL correlated with hsCRP and creatinine in HDF patients. Conclusions: Residual renal function seems to play a pivotal role in NGAL levels in dialyzed patients. Low-grade inflammation, more pronounced in anuric patients may also contribute to elevated NGAL. Removal of NGAL with ultrafiltrate may also partially explain its lower concentration after dialysis.