Changes of Blood and Urinary Interleukin-8 (IL-8) and Tumor Necrosis Factor-alpha (TNF-alpha) in Children with Minimal Change Nephrotic Syndrome, and Changes of Heparan Sulfate Proteoglycan mRNA Expression by IL-8 and TNF-alpha in Rats Glomerular Epithelial Cells

Kim, Ji Yoon; Cho, Min Hyun; Ko, Cheol Woo; Koo, Ja Hoon

Abstract

BACKGROUND: Minimal Change Nephrotic Syndrome (MCNS) is one of the most common primary nephrotic syndromes in children and its pathogenesis has not been exactly known. Interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha ) may be involved in the pathogenesis of this disese, because they are increased in blood and/or urine during relapse. This study was conducted to see changes of IL-8 and TNF-alpha in children with MCNS and to see the effects of IL-8 and TNF-alpha on the abundance of HSPG mRNA in rats glomerular epithelial cells (GECs).
METHODS
Study patients consisted of 19 biopsy-proven MCNS children aged 2-15 years old. Ten age-matched healthy children were used as controls. Both blood and urinary IL-8 and TNF-alpha were measured using ELISA kit. GECs were cultured until confluent. IL-8 or TNF-alpha were added at various concentrations. Total RNA was extracted at 12 or 24 hours after adding IL-8 or TNF-alpha . RT-PCR using HSPG-specific primers and beta-actin as internal controls was done. Densities and areas of GBM HSPG corresponding bands to beta-actin bands were measured.
RESULTS
Values of urinary IL-8 (ng/mg'cr) were 13,996+/-2,811, 2,811+/-3,734, and 5,331+/-6,403, during relapse, remission, and in control, respectively. Urinary IL-8 'during relapse' was significantly measured increased compared to 'during remission' and in controls (p<0.05). Values of urinary TNF-alpha (ng/mg'cr) were 364.4+/-512.1, 155.3+/-208.0, and 36.0+/-45.0, during relapse, remission, and in control, respectively. Urinary TNF-alpha during relapse was also significantly increased compared to 'during remission' and 'control' (p<0.05). Values of Blood IL-8 (ng/mL) were 1.19+/-1.23, 0.51+/-0.84, and 0.77+/-0.62, during relapse, remission, and in control, respectively. Blood IL-8 during relapse was significantly increased compared to 'during remission' and 'in control' (p<0.05). No significant change was seen in blood TNF-alpha. And no significant difference was seen in abdundance of HSPG mRNA after adding various concentraons IL-8 or TNF-alpha into rats GEC.
CONCLUSION
The values of plasma and urinary IL-8 and TNF-alpha during relapse were increased compared to those of remission period and in control. but neither IL-8 nor TNF-alpha affect the abundance of HSPG-mRNA in rats GECs at various concentraions. So, it seems that both IL-8 and TNF-alpha do not play a direct role in GBM permeability and the elevated values of these cytokines in plasma and/or urine are secondary effects.