Gene Expression Of Heparanase In Peripheral Blood Leukocytes Of Nephrotic Syndrome And Relevance For Proteinuria

Objective: The β-D-endoglycosidase heparanase (Hpa) is HS-specific which leads to heparan sulfate (HS) degradation. An increased permeability of the GBM for proteinuria is related with a decreased HS side chains of the GBM. However, whether an Up-regulated expression of Hpa exists in nephrotic syndrome remains unknown.The purpose of this study was to evaluate the role of Hpa in the development of steroid responsive and simple nephrotic syndrome (SRSNS) and adriamycin(ADR)-induced nephrotic syndrome(NS) and relevance for proteinuria.Methods: (1 )Forty-three children with SRSNS were selected,including the active stage group(n=23),the restoration stage group(n=10),the remission stage group(n=10).The peripheral blood leukocytes (PBLs) from 23 nephritic nephrosis ,15 purpura nephritis and 15 healthy children were served as the control.(2) NS was induced in 150-200g Sprague-Dawley rats(n=6 per group) by tail intravenous injection of 6 mg/kg ADR. Rats were housed in metabolic cage for 24 hours to collect urine prior to induction of disease and at day 7 and 14 following disease induction. By using the method of reverse transcriptase-PCR (RT-PCR),Hpa gene from PBLs of these groups was assayed respectively.Results: (1)A11 NS exhibited higher levels of Hpa mRNA than the healthy group(P<0.05).The active stage group of SRSNS (1.2747 ±0.3614) was the highest one of all (P<0.001).In contrast with the healthy group, there was significant difference between the active stage group(P<0.001)and the restoration group(P<0.05) of SRSNS, but no difference to the remission stage group. There was a significant correlation between the level of Hpa mRNA and the quantification of urinary protein. As the expression level of Hpa mRNA was higher , the quantification of urinary protein was more (rs=0.751,P<0.001).But they had no difference between the first-onset and the recurrent children of SRSNS. (2)The resulting cDNA fragment was consistent with rat heparanase mRNA sequence in GenBank(accession number AF184963);Rats at day 7 and 14 showed marked up-regulated Hpa mRNA and had significant difference in contrast to the normal rats.Leukocytes of rats at day 14 was the highest (1.1339 ±0.22ll),then at day 7 was 0.6601± 0.1724,the normal was 0.3578 ± 0.1235.The expression level of Hpa mRNA in these groups exhibited a linear tendency(F=57.771,P<0.001);There was a significant correlation between the expression level of Hpa mRNA and the quantification of urinary protein(rs=0.925,P<0.001) .Conclusion: Up-regulated expression of Hpa mRNA may be an importanr contributor to loss of glomerular negative charge in GBM and lead to proteinuria. Higher Hpa mRNA expression,more quantitation of urinary protein. SRSNS and ADR-induced nephrotic syndrome have the consistent result.