Diagnostic efficacy of serum and urinary netrin-1 in the early detection of diabetic nephropathy.

This study aimed to assess the diagnostic value of serum and urinary netrin-1 in patients with type 2 diabetes mellitus (T2DM) at different stages of diabetic nephropathy (DN) and to compare its efficacy of estimation in serum with that in the urine. This study was carried out on 135 patients with T2DM and 45 healthy subjects. The patients with diabetes were divided according to urinary albumin creatinine ratio (UACR) into: T2DM with normoalbuminuria, incipient DN with microalbuminuria, and overt DN with macroalbuminuria groups. Serum and urinary levels of netrin-1 were measured by ELISA. The mean levels of serum and urinary netrin-1 were significantly higher in the microalbuminuric and macroalbuminuric patients with DN than those in the normoalbuminuric patients with T2DM, with the highest values detected in macroalbuminuric patients with DN. Urinary netrin-1 level was significantly higher in the normoalbuminuric T2DM group than control group, whereas no significant difference existed regarding serum netrin-1 level. In T2DM groups, the urinary and serum netrin-1 correlated with each other and were independently related to fasting blood glucose, UACR, and estimated glomerular filtration rate. Receiver operating characteristic curve analysis showed that the area under the curve of urinary netrin-1 was 0.916 which is significantly higher than that of serum netrin-1 (0.812) for the detection of incipient DN and reached 0.938 on coestimation of both urinary and serum netrin-1. In conclusion, netrin-1 is a potential diagnostic marker for early detection of DN with its estimation in urine has higher accuracy than that of serum.