[Damage to proximal tubular epithelial cells in type 2 diabetes mellitus].

Introduction: Kidney damage from diabetes mellitus is called diabetic nephropathy. At the beginning it is a functional disorder, but later it results in an irreversible damage. The aim of this research was to establish damage to proximal tubular cells in patients with type 2 diabetes mellitus, and various degrees of proteinuria by determining the urinary N-acetyl-beta-D-glucose-aminidase and gamma-glutamyl-transferase; to compare obtained results with the results in healthy examinees; to establish the correlation between these enzymes, and to investigate their sensitivity.

Material And Methods: Patients with type 2 diabetes mellitus and creatinine clearence >80 ml/min were included in the research. Patients were divided into three groups, according to the degree of proteinuria. The first group included diabetics without microalbuminuria; the second--patients with proteinuria <300 mg/24 h and microalbuminuria >20 mg/24 h, and the third group included patients with proteinuria >300 mg/24 h. Healthy examinees were the control group.

Results: Values of the urinary N-acetyl-beta-D-glucosaminidase activity were elevated before microalbuminuria was observed. The highest values were detected in the group of patients with microalbuminuria. Differences among the examined groups were statistically significant, which implies that this enzyme has a high diagnostic importance. Enzyme gamma-glutamyl-transferase was less sensitive in this research. The activity of this enzyme was increased only in the group of patients with proteinuria >300 mg/24h, where values increased with diabetes mellitus duration.

Conclusion: The increased activity of urinary N-acetyl-beta-D-glucosaminidase points to early tubular damage, and can be used as a sensitive parameter in its early detection. On the other hand, gamma-glutamyl-transferase was a less sensitive damage indicator.