Quantitative iTRAQ-Based Proteomic Identification of Candidate Biomarkers for Diabetic Nephropathy in Plasma of Type 1 Diabetic Patients

# The Author(s) 2010. This article is published with open access at Springerlink.com Introduction As part of a clinical proteomics programme focused on diabetes and its complications, it was our goal to investigate the proteome of plasma in order to find improved candidate biomarkers to predict diabetic nephropathy. Methods Proteins derived from plasma from a crosssectiona

ß2-microglobulin and cystatin C in type 2 diabetes: Assessment of diabetic nephropathy

PubMed ID: 15127324Background: Changes in glomerular filtration rate (GFR) provide a valuable indicator of the progression of diabetic nephropathy (DN). This study was designed to demonstrate the clinical values of serum cystatin C (Cys C) and ß2-microglobulin in the assessment of renal function in type 2 diabetics by comparing them with the GFR, estimated from the uptake phase of 99 m technetium dimetiltriamino pentaacetic acid renogram (GFR-DTPA) and creatinine clearances. Materials and Methods: 68 type 2 diabetic patients with (urinary albumin excretions (UAE) 30-300 mg/24 h) (n = 39) and without (UAE < 30 mg/ 24 h) (n = 29) microalbuminuria and 32 controls were enrolled in the study. Serum Cys C, ß2-microglobulin, creatinine, urinary microalbumin levels, creatinine clearances and GFR-DTPA values were determined in all groups. Non-parametric ROC curves, using a cut-off GFR-DTPA of 60 mL/min/1.73 m 2, were obtained for these markers. Results: Serum Cys C, ß2-microglobulin, glucose and HbA1c concentrations were significantly higher in the group with diabetes compared to controls. In the patients with microalbuminuria, serum Cys C and glucose concentrations increased significantly in comparison to patients with normoalbuminuria, while no differences were observed for ß2-microglobulin levels. Serum creatinine concentrations, GFR-DTPA values and creatinine clearances were not different between both diabetic groups and controls. Cys C was positively correlated with ß2-microglobulin and creatinine and negatively with GFR values; ß2-microglobulin was also positively correlated with serum creatinine in microalbuminurics. A significant inverse correlation was found between ß2-microglobulin and GFR values in both microalbuminurics and normoalbuminurics. Conclusions: Increased Cys C and ß2-microglobulin in diabetics may be early indicators of incipient DN. The diagnostic accuracies of Cys C and ß2-microglobulin are superior to that of serum creatinine in distinguishing between mild and moderately reduced GFR