Assessment of nephrin and podocin levels in the urine of patients with diabetes mellitus
THE AIM: to assess excretion value of podocytes injury biomarkers in urine and to clarify their significance for early diabetic nephropathy (DN) diagnostics in diabetes mellitus (DM) patients with different severity of albuminuria (AU)/proteinuria(PU). PATIENTS AND METHODS. 74 DM pts were studied, including 30 with type1 DM (T1DM) and 44 pts with type2 DM (T2DM). They were divided into three groups: 41 pts with AU <30 mg/gCr (A1), 13 pts with AU 30-300 mg/gCr (A2), 20 pts with PU (A3). CKD S1 was revealed in 41pts, CKD S2 - in 25 pts, CKD S3 - in 8 pts. Arterial hypertension was observed in 52 pts of 74(70%), mainly in T2DM. 10 healthy subjects were studied as control. Urinary levels of nephrin and podocin (an important slit diaphragm proteins) were measured by ELISA. RESULTS. Nephrinuria (NU) >5,84ng/ml/g, which not detecting in controls, was revealed in 63% of A1 pts, in 77% - in A2, in 80% - in A3. Podocinuria (PdU)>1,73ng/ml/g was revealed in 78% of A1 pts, in 54% of A2 and in 83% - A3. NU in pts with PU was significantly higher than in AU<30 mg/g. PDU in groups with different AU/PU was equally high and has no differ between DM types. Direct correlation was obtained between NU and AU (R=0,947 p<0,05). NU and PdU in T1DM correlated directly with serum creatinine (R=0,489 p<0,05 and R=0,468 p<0,05) and indirectly with GFR (R=-0,461 p<0,05 and R=-0,36 р<0,05). In DM duration less than 5 years NU directly correlated with НЬА1с level, in T2DM - indirectly with systolic blood pressure. CONCLUSON. Nephrin and podocin levels can be useful for early diagnostics and monitoring of DN.