Pathological and prognostic value of urinary neutrophil gelatinase-associated lipocalin in macroproteinuric patients with worsening renal function.

BACKGROUND/AIMS: Persistent proteinuria is a sign of renal damage caused by several factors, but it is itself a cause of tubular injury leading to chronic renal failure. Neutrophil gelatinase-associated lipocalin (NGAL) is a stress protein released by tubular cells which urinary excretion (uNGAL) increases in response to various stimuli.

METHODS

In the present study we analyzed uNGAL levels in 23 macroproteinuric patients with membranous glomerulonephritis.

RESULTS

In these subjects, uNGAL concentrations were significantly higher than in controls, directly correlated with proteinuria and inversely related to residual renal function. Patients were further categorized into two groups, according to a cut-off baseline uNGAL value of 350 ng/ml and evaluated during a 1-year follow-up period. After 12 months, subjects with higher uNGAL levels showed a significant worsening in baseline renal function and a 3.36 risk ratio of developing a severe decrease in GFR (>or=50% of baseline values) compared with others.

CONCLUSIONS

These findings suggest that NGAL may play a key role in tubular adaptations to persistent macroproteinuria. Furthermore, a new, interesting application of NGAL measurement could be proposed in clinical nephrology as a predictor of worsening renal function in patients affected by chronic kidney disease.