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

Abstract

Objectives: To study the urinary neutrophil gelatinase-associated lipocalin (NGAL) and beta-2-microglobulin (β2M) 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 β2M 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) µg/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 β2M/creatinine [1.7 (0.43, 6.02) and 2.12 (1.05, 4.47) µg/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 β2M/creatinine (r=0.42, p=0.009).

Conclusions: Urinary biomarkers NGAL and β2M were elevated in the presence of normal urinary microalbumin levels suggestive of early tubular damage in T1DM.

Keywords: NGAL; complications; diabetes kidney disease; hyperfiltration; microalbuminuria; microvascular.