Exp Clin Endocrinol Diabetes 2004; 112(4): 195-200
DOI: 10.1055/s-2004-817933
Article

J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York

β2-Microglobulin and Cystatin C in Type 2 Diabetes: Assessment of Diabetic Nephropathy

S. Apakkan Aksun1 , D. Özmen1 , B. Özmen2 , Z. Parildar1 , I. Mutaf1 , N. Turgan1 , S. Habif1 , K. Kumanlioğluc3 , O. Bayindir1
  • 1Department of Clinical Biochemistry, Ege University Faculty of Medicine, Bornova, Izmir, Turkey
  • 2Department of Endocrinology, Celal Bayar University Faculty of Medicine, Manisa, Turkey
  • 3Department of Nuclear Medicine, Ege University Faculty of Medicine, Bornova, Izmir, Turkey
Further Information

Publication History

Received: January 9, 2003 First decision: February 24, 2003

Accepted: May 12, 2003

Publication Date:
04 May 2004 (online)

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Abstract

Background: 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 β2-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, β2-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 m2, were obtained for these markers.

Results: Serum Cys C, β2-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 β2-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 β2-microglobulin and creatinine and negatively with GFR values; β2-microglobulin was also positively correlated with serum creatinine in microalbuminurics. A significant inverse correlation was found between β2-microglobulin and GFR values in both microalbuminurics and normoalbuminurics.

Conclusions: Increased Cys C and β2-microglobulin in diabetics may be early indicators of incipient DN. The diagnostic accuracies of Cys C and β2-microglobulin are superior to that of serum creatinine in distinguishing between mild and moderately reduced GFR.

References

M. D. Zuhal Parildar

Department of Clinical Biochemistry
Ege University Faculty of Medicine

35100 Bornova · Izmir

Turkey

Email: zuhalp@med.ege.edu.tr