To investigate relationships among urinary biomarkers [kidney injury molecule-1 (KIM-1), N-acetyl-β-glucosaminidase (NAG)], neutrophil gelatinase-associated lipocalin (NGAL) levels and renal tubular injury in childhood urolithiasis.
Seventy children [36 girls, mean age: 7.3 ± 5.0 years (0.5-18.2)] with urolithiasis/microlithiasis and 42 controls [18 girls, mean age: 8.5 ± 3.8 years (0.9-16.2)] were included in this multicenter, controlled, prospective cohort study. Patients were evaluated three times in 6-month intervals (0, 6 and 12th months). Anthropometric data, urinary symptoms, family history and diagnostic studies were recorded. Urine samples were analyzed for metabolic risk factors (urinary calcium, uric acid, oxalate, citrate, cystine, magnesium, and creatinine excretion), and the urinary KIM-1, NAG, and NGAL levels were measured.
Stones were mostly located in the upper urinary system (82.9%), and six patients (8.6%) had hydronephrosis. Thirty patients (42.9%) had several metabolic risk factors, and the most common metabolic risk factor was hypocitraturia (22.9%). Urinary KIM-1/Cr, NAG/Cr and NGAL/Cr ratios were not significantly different between patients and controls. Furthermore, no significant changes in their excretion were shown during follow-up. Notably, the urinary KIM-1/Cr, NAG/Cr, and NGAL/Cr levels were significantly higher in children under 2 years of age (p = 0.011, p = 0.006, and 0.015, respectively). NAG/Cr and NGAL/Cr ratios were significantly increased in patients with hydronephrosis (n = 6, p = 0.031 and 0.023, respectively).
The results of this study suggest that none of the aforementioned urinary biomarkers (KIM-1, NAG and NGAL levels) may be useful for the early detection and/or follow-up of renal tubular injury and/or dysfunction in childhood urolithiasis.
Clinical and experimental nephrology. 2017 Jun 26 [Epub ahead of print]
Mehmet Taşdemir, Dilara Fuçucuoğlu, Suat Hayri Küçük, Meltem Erol, Özgül Yiğit, Ilmay Bilge
Division of Pediatric Nephrology, Department of Pediatrics, Koç University Hospital, Davutpaşa cad no: 4 Topkapı, 34010, Istanbul, Turkey. ., Department of Pediatrics, Ministry of Health, Bağcılar Training and Research Hospital, Merkez mah, Mimar Sinan cad, 6. sok, Bağcılar, Istanbul, Turkey., Department of Biochemistry, Ministry of Health, Bağcılar Training and Research Hospital, Merkez mah, Mimar Sinan cad, 6. sok, Bağcılar, Istanbul, Turkey., Division of Pediatric Nephrology, Department of Pediatrics, School of Medicine, Koc University, Davutpaşa cad no: 4 Topkapı, 34010, Istanbul, Turkey.