Study of Urinary N-Acetyl-Beta-D-Glucosaminidase as a biomarker of Diabetic Nephropathy

Background: Diabetic nephropathy (DN) is a major cause of morbidity and mortality in diabetic patients worldwide. Plenty of tubular damage biomarkers have been discovered. Urinary N-acetyl-β-D-glucosaminidase (NAG) is a hydrolytic enzyme that acts on glycosyl compounds. NAG is excreted in abnormally high amounts in many renal diseases. Objective: The aim of this work was to study the importance of Urinary N acetyl-β-D-glucosaminidase level as an early biomarker for detection of DN and to assess the degree of kidney affection in various stages of DN. Patients and methods: 100 subjects divided into five groups: Group 1: 20 healthy volunteers (control group), group 2: 20 pre diabetic persons, group 3: 20 normo-albuminuria diabetic patients, group 4: 20 micro-albuminuria diabetic patients (ACR 3 -300 mg/mmol) and group 5: 20 macro-albuminuria diabetic patients (ACR ≥ 300 mg/mmol). All individuals were subjected to full history taking, ECG & echocardiography, abdominal ultrasound, laboratory investigations (HbA1c, fasting and post prandial blood glucose, lipid profile, oral glucose tolerance test (OGTT), blood urea, serum creatinine, serum uric acid, e-GFR and urinary NAG. Results: There was high significant difference between the five groups regarding duration of the disease, fasting blood sugar, postprandial blood glucose, HbA1c, Serum cholesterol, albumin/creatinine ratio, serum urea and creatinine, e-GFR and urinary NAG. In addition, there was significant positive correlation between urinary NAG and albumin/creatinine ratio, blood urea, creatinine, and e-GFR. Conclusion: The urinary NAG can be used as an early urinary biomarker for early detection and progression of diabetic nephropathy in type 2 diabetic patients.