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Background and objectives: Chronic kidney disease (CKD) has recently assumed epidemic proportion, becoming a troubling emerging cause of morbidity, especially if it progresses to terminal stage (ESRD). The authors aimed to evaluate whether neutrophil gelatinase-associated lipocalin (NGAL), a novel specific biomarker of acute kidney injury, could predict the progression of CKD.Design, setting, participants, & measurements: Serum and urinary NGAL levels, together with a series of putative progression factors, were evaluated in a cohort of 96 patients (mean age: 57 ؎ 16 years) affected by nonterminal CKD (eGFR >15 ml/min/1.73 m 2 ) of various etiology. Progression of CKD, assessed as doubling of baseline serum creatinine and/or onset of ESRD, was evaluated during follow-up.Results: At baseline, both serum and urinary NGAL were inversely, independently, and closely related to eGFR. After a median follow-up of 18.5 mo (range 1.01 to 20), 31 patients (32%) reached the composite endpoint. At baseline, these patients were significantly older and showed increased serum creatinine, calcium-phosphate product, C-reactive protein, fibrinogen, daily proteinuria, and NGAL levels, whereas eGFR values were significantly lower. Univariate followed by multivariate Cox proportional hazard regression analysis showed that urinary NGAL and sNGAL predicted CKD progression independently of other potential confounders, including eGFR and age.Conclusion: In patients with CKD, NGAL closely reflects the entity of renal impairment and represents a strong and independent risk marker for progression of CKD.

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Background/Aims: Renal tubulointerstitium plays an important role in the development and progression of diabetic nephropathy. Methods: With the present study, we aimed at evaluating the levels of neutrophil gelatinase-associated lipocalin (NGAL), a tubular stress protein, in serum (sNGAL) and urine (uNGAL) from a cohort of 56 patients with type 2 diabetes mellitus categorized into three groups (normoalbuminuria, microalbuminuria and diabetic nephropathy). Results: All groups showed increased NGAL values with respect to controls; interestingly, increased NGAL levels were already found in diabetic patients without early signs of glomerular damage (normoalbuminuric). Both sNGAL and uNGAL increased in parallel with the severity of renal disease, reaching higher levels in patients with manifest diabetic nephropathy. The assessment of Pearson coefficient evidenced significant relationships between sNGAL and, respectively, uNGAL, serum creatinine and GFR (inversely) and between uNGAL and, respectively, serum creatinine, proteinuria, albuminuria, serum albumin and GFR (both inversely). Conclusions: NGAL might play an important role in the pathophysiology of renal adaptation to diabetes, probably as a defensive mechanism aiming to mitigate tubular suffering. Furthermore, NGAL measurement might become a useful and noninvasive tool for the evaluation of renal involvement in diabetic patients as well as for the early diagnosis of incipient nephropathy.

Neutrophil gelatinase-associated lipocalin (NGAL) is a small 25-kDa protein released from kidney tubular cells after harmful stimuli. It represents one of the most promising future biomarkers in the diagnostic field of acute kidney injury (AKI), as the increase in NGAL levels is a good predictor of a brief-term onset of AKI, notably anticipating the resulting increase in serum creatinine. However, recent studies also suggest a possible role for NGAL in chronic kidney disease (CKD). For this reason we evaluated serum (sNGAL) and urinary NGAL (uNGAL) in a cohort of CKD patients in order to verify the relationship with the severity of renal impairment. In CKD patients sNGAL, uNGAL and the fractional excretion of this protein were notably increased as compared to controls. Furthermore both sNGAL and uNGAL were correlated with serum creatinine and, inversely, with residual glomerular filtration rate (GFR): this last relationship was found to be even closer than that found between GFR and serum creatinine. Multivariate models validate these correlations as independent, confirming that in these patients NGAL is a better predictor of GFR than serum creatinine. The results confirm NGAL as an important biomarker in clinical nephrology, extending to CKD the pathophysiological role of this protein in tubular adaptations to renal damage.