Intrarenal renin–angiotensin system activation and macrophage infiltrations in pediatric chronic glomerulonephritis

Abstract Background The current study tested the hypothesis that urinary angiotensinogen (UAGT) and urinary monocyte chemoattractant protein-1 (UMCP-1) levels provide a specific index of intrarenal renin–angiotensin system (RAS) status and the degree of infiltration of macrophages associated with RAS blockade and immunosuppressant treatment in pediatric patients with chronic glomerulonephritis. Methods We measured baseline UAGT and UMCP-1 levels to examine the correlation between glomerular injury in 48 pediatric chronic glomerulonephritis patients before treatment. Furthermore, we performed immunohistochemical analysis of angiotensinogen (AGT) and CD68 in 27 pediatric chronic glomerulonephritis patients treated with RAS blockades and immunosuppressants for 2 years. Finally, we examined the effects of angiotensin II (Ang II) on monocyte chemoattractant protein-1 (MCP-1) expression in cultured human mesangial cells (MCs). Results Baseline UAGT and UMCP-1 levels positively correlated with urinary protein levels, scores for mesangial hypercellularity, rate of crescentic formation, and expression levels of AGT and CD68 in renal tissues ( p < 0.05). UAGT and UMCP-1 levels were significantly decreased after RAS blockade and immunosuppressant treatment ( p < 0.01), which was accompanied by AGT and CD68 ( p < 0.01), as well as the magnitude of glomerular injury. Cultured human MCs showed increased MCP-1 messenger ribonucleic acid and protein levels after Ang II treatment ( p < 0.01). Conclusions The data indicates that UAGT and UMCP-1 are useful biomarkers of the degree of glomerular injury during RAS blockade and immunosuppressant treatment in pediatric patients with chronic glomerulonephritis.