Vittori M et al, 2016: Neutrophil gelatinase-associated lipocalin (NGAL) value changes before and after shock wave lithotripsy.
Vittori M, Baroni S, Ferraro PM, Gambaro G, Morelli R, Bassi P, D'Addessi A.
Division of Urologic Surgery, Division of Biochemistry, Division of Nephrology, Division of Urology, Division of Urologic Surgery, Policlinico A. Gemelli-Columbus Foundation, Catholic University School of Medicine, Largo A. Gemelli 8, 00168, Rome, Italy.
Abstract
Our aim was to determine short and medium-term changes of neutrophil gelatinase-associated lipocalin (NGAL) in the urine of patients undergoing shock wave lithotripsy (SWL). In patients with kidney stones, serum urea and creatinine (Cr), urine Cr and NGAL levels were determined immediately before and at 3, 24 h and 30 days after SWL. Urine NGAL concentrations were normalized to urinary Cr ruling out the confounding effect of variable hydration states. Thirty-five patients with a single renal stone were enrolled. Inclusion criteria were: first SWL treatment for each patient, single radiopaque renal stone <20 mm; normal renal function. Exclusion criteria were: body mass index (BMI) > 30 kg/m2, recent episodes of renal colic (less than 3 months), the presence of radiolucent stones, renal impairment, upper urinary tract obstruction or malignancy, acute pyelonephritis, patients who consumed potentially nephrotoxic drugs within 4 weeks before the evaluation. Geometric means of urinary NGAL/Cr ratio measured 3 h after SWL were significantly higher than baseline values (difference 7.56 ng/mg, 95% confidence interval 1.61, 13.51; p value = 0.013). No changes were found for urinary NGAL/Cr measured at 24 h (p value = 0.92) and at 30 days (p value = 0.13) after SWL compared with baseline values. Urinary NGAL levels increase soon after SWL (3 h) and quickly return to and maintain basal levels (1 and 30 days). Further studies are necessary to understand the hypothetical role of NGAL as a guide to the degree of tissue injury after SWL.
Urolithiasis. 2016 Oct 27. [Epub ahead of print]
Comments 1
In attempts to discover kidney damage the authors measured NGAL (neutrophil gelatinase-associated lipocalin) in urine before and after SWL. NGAL was slightly increased after 3h but had returned to normal (pre-treatment) levels at 24h and was also normal after 30 days.
The aim was to find a sensitive tool for measuring kidney damage and the authors stated that “Many potential markers have been studied with disappointing results”. Disappointing in which perspective? Disappointing because they were not sensitive enough or disappointing because they did not indicate kidney injuries?
That the authors did not find a relationship between the NGAL rise and SW-load is not surprising inasmuch as all patients were treated according to the same protocol.
The relevance by measuring NGAL is not clear, because in this series of treatments the discrete rise is probably without clinical significance. Measuring NGAL might however be of importance in order to evaluate and compare different treatment protocols [1].
Reference
1. Vittori M, Baroni S, Ferraro PM, Gambaro G, Morelli R, Bassi P, D'Addessi A.
Neutrophil gelatinase-associated lipocalin (NGAL) value changes before and after shock wave lithotripsy.
Urolithiasis. 2016 Oct 27. [Epub ahead of print]