Original Paper

Messenger RNA Expression of Podocyte-Associated Molecules in the Urinary Sediment of Patients with Diabetic Nephropathy
Gang Wang^a, Fernand Mac-Moune Lai^b, Ka-Bik Lai^a, Kai-Ming Chow^a, Kam-Tao Philip Li^a, Cheuk-Chun Szeto^a

Departments of
^aMedicine and Therapeutics and
^bAnatomical and Cellular Pathology, Prince of Wales Hospital, Chinese University of Hong Kong, Hong Kong, SAR, China

Address of Corresponding Author

Nephron Clin Pract 2007;106:c169-c179 (DOI: 10.1159/000104428)

  Key Words

• Diabetes mellitus
• Nephrin
• Urinalysis

  Abstract

Background: Podocyte loss plays an important role in the pathogenesis of diabetic nephropathy. We hypothesize that messenger RNA expression of podocyte-associated molecules in urinary sediment may provide important clinical information in patients with diabetic nephropathy. Method: We studied 21 patients with biopsy-proven diabetic nephropathy and 9 healthy controls. The mRNA expression of nephrin, podocin, synaptopodin, Wilms' tumor-1 (WT-1) and -actinin-4 in urinary sediment were measured by real-time quantitative polymerase chain reaction. The degree of histological damage was quantified by morphometric analysis. Patients were then followed for an average of 25.63 ± 10.76 months. The rate of glomerular filtration rate (GFR) decline was calculated by the least-square regression. Results: There were significant differences in nephrin, podocin, synaptopodin, -actinin-4 (p < 0.01 for all comparisons) and WT-1 (p = 0.028) expression between patients and normal controls. Urinary nephrin expression was significantly correlated with proteinuria (r = 0.502, p = 0.020); urinary synaptopodin was significantly correlated with proteinuria (r = 0.585, p = 0.005), serum creatinine (r = 0.516, p = 0.017) and estimated GFR (r = -0.560, p = 0.008), and urinary WT-1 expression was significantly correlated with the degree of tubulointerstitial fibrosis (r = 0.558, p = 0.009). There was no significant correlation between GFR decline and urinary expression of target genes. Conclusion: Urinary mRNA expressions of nephrin, podocin, synaptopodin, WT-1 and -actinin-4 are higher in patients with diabetic nephropathy than in normal controls. Urinary nephrin and synaptopodin expressions are correlated with baseline clinical parameters such as proteinuria or renal function, while WT-1 expression is related to the degree of histological damage. Our results suggest that urinary mRNA expression of podocyte-associated molecules may be used for risk stratification of diabetic nephropathy.

Copyright © 2007 S. Karger AG, Basel

  Author Contacts

Dr. Cheuk-Chun Szeto
Department of Medicine and Therapeutics, Prince of Wales Hospital
Chinese University of Hong Kong
Shatin, NT, Hong Kong, SAR (China)
Tel. +852 2632 3126, Fax +852 2637 3852, E-Mail ccszeto@cuhk.edu.hk

  Article Information

Received: December 8, 2006
Accepted: March 8, 2007
Published online: June 26, 2007
Number of Print Pages : 11
Number of Figures : 4, Number of Tables : 2, Number of References : 39