OBJECTIVEThe beta-D-endoglycosidase heparanase (Hpa) is HS-specific which leads to the degradation of heparan sulfate (HS). An increased permeability of the glomerular basement membrane (GBM) for proteinuria was suggested to relate to a decrease of HS side chains in the GBM. However, whether an up-regulated expression of Hpa exists in steroid responsive nephrotic syndrome (SRSNS) remains unknown. The purpose of this study was to evaluate the role of Hpa in the development of SRSNS and the correlation with the proteinuria.

METHODSForty-three children with SRSNS were selected and included the active stage group (n = 23), the restoration stage group (n = 10) and the remission stage group (n = 10). There were 23 nephritic nephrosis children, 15 purpura nephritis children and 15 healthy children as controls. By using the method of reverse transcriptase-PCR (RT-PCR), Hpa gene expression in the peripheral blood leukocytes (PBLs) was assayed.

RESULTS(1) All patients with nephrotic syndrome exhibited higher levels of Hpa mRNA than those of the healthy group (P < 0.05). The highest expression was in the active stage group of SRSNS (1.27 +/- 0.36, P < 0.001), while there was no difference between the patients of nephritic nephrosis group (0.62 +/- 0.15) and purpura nephritis group (0.55 +/- 0.17) (P > 0.05). (2) In contrast with the healthy group, there was a significant difference in the active stage group of SRSNS (P < 0.001). So was the restoration stage group (P < 0.05), but there was no difference to the remission stage group (P > 0.05). (3) There was a positive correlation between the expression level of Hpa mRNA and the quantity of urinary protein (r(s) = 0.751, P < 0.001).

CONCLUSIONUp-regulated expression of Hpa mRNA may be important to the loss of glomerular negative charge in GBM and lead to proteinuria in SRSNS.