Urinary biomarkers NG AL and beta-2 microglobulin in children with type 1 diabetes mellitus

Objectives To study the urinary neutrophil gelatinase-associated lipocalin (NGAL) and beta-2-microglobulin (beta 2M) levels as markers of tubular damage in children with type 1 diabetes (T1DM). Methods Forty T1DM children and 40 age-matched controls were enrolled. Subjects with coexisting kidney disorder, intake of oral glucose lowering drugs and syndromic diabetes mellitus were excluded. Fasting plasma glucose, glycated hemoglobin (HbA(1c)), kidney function, urinary albumin-creatinine ratio (UACR), NGAL and beta 2M were measured and compared in cases and controls. Results The median (IQR) age of cases and controls was 10.6 (8, 14.2) and 10.7 (8.4, 13.7) years, respectively. Cases had disease duration of 4 (3, 6.8) years and HbA(1c) 10.9 (9, 13.1) %. Microalbuminuria was seen in 14 (35 %). Median (IQR) levels of UACR were higher in cases than controls [19.38 (10.27, 35.26) and 6.49 (3.10, 11.65) mu g/mg; p<0.001], similarly NGAL/creatinine [352.21 (191.49, 572.45) and 190.54 (125.91, 322.83) ng/mg; p=0.006], unlike beta 2M/creatinine [1.7 (0.43, 6.02) and 2.12 (1.05, 4.47) <mu>g/mg; p=0.637]. Children with higher HbA(1c) (>= 10 %) had higher urinary ACR and tubular biomarkers than HbA(1c)<10 % (p>0.05). Urinary ACR showed positive correlation with NGAL/creatinine (r=0.38, p=0.019) and beta 2M/creatinine (r=0.42, p=0.009). Conclusions Urinary biomarkers NGAL and beta 2M were elevated in the presence of normal urinary microalbumin levels suggestive of early tubular damage in T1DM.