Urinary Neutrophil Gelatinase Associated Lipocalin as a Marker of Tubular Damage in Type 2 Diabetic Patients with and without Albuminuria

Background: Neuttrophil gelatinase associated lipocalin (NGAL) was shown to be a good marker for predicting acute kidney injury (AKI). Some recent reports demonstrated that NGAL may be an early biomarker for kidney affection in diabetic patients. The aim of this work is to investigate urinary NGAL (UNGAL) in type 2 diabetic patients with and without albuminuria. Methods: This study included 46 type 2 diabetic patients and 15 healthy age and sex matched individuals as the control group. Diabetic patients were divided into three groups according to urinary albumin excretion (UAE), normoalbuminuria, microalbuminuria and macroalbuminuria. UNGAL was measured in all populations and corrected to urinary creatinine to account for day to day variation in urine volume and transformed log. Comparison between 4 groups (control, normoalbuminuria, microalbuminuria and macroalbuminuria) was done. Results: Log UNGAL/Creatinine ratio showed significant difference when comparing control group (0.70 ± 0.58) versus normoalbuminuria (1.71 ± 1.06), microalbuminuria (1.57 ± 0.72) and macroalbuminuria (1.92 ± 0.63), however, there was no significant difference among diabetic groups. Pearson’s correlation showed that log UNGAL/Creatinine ratio positively correlated with glycated hemoglobin (HbA1c) and inversely with estimated glomerular filtration rate (eGFR). Regression analysis showed that HbA1c, urinary creatinine and eGFR were the independent predictors of log UNGAL/Creatinine ratio. Conclusion: Tubular markers like UNGAL may be early elevated in type 2 diabetic patients even before the incidence of glomerular injury detected by microalbuminuria and it can be used as an early marker for detection of kidney involvement in diabetic patients.