Differential effects of FMLP-activated neutrophils from patients with IgA nephropathy enhanced endothelin 1 production of glomerular mesangial cells

Background. Neutrophil infiltration in the glomeruli is common in patients with IgA nephropathy (IgAN). The pathogenetic roles of the infiltrated neut rophils and their relationship with glomerular mesangial cells, however, ar e not clear. Methods: We examined the effects of coculture with N-formyl-me thionyl-leucyl-phenylalanine (FMLP) activated neutrophils on the viability, endothelin 1 (ET-1) production, and ET-1 mRNA expression of rat glomerular mesangial cells. Neutrophils were isolated from 15 IgAN patients, from 13 patients with non-IgA mesangial proliferative glomerulonephritis (MsPGN), a nd from 10 normal controls. Results: The ET-1 production by mesangial cells was significantly higher after stimulation with FMLP-activated neutrophils from IgAN patients than that of MsPGN patients and normal controls, and th is effect was significantly abolished by pretreating mesangial cells with s uperoxide dismutase and partly abolished by catalase. The ET-1 mRNA express ion of mesangial cells showed a parallel increase with ET-1 protein. The tr ypan blue exclusion test showed significant mesangial cell death after stim ulation with FMLP-activated neutrophils as compared with quiescent neutroph ils, and the cell death was also prevented by super- oxide dismutase but no t catalase. The FMLP-activated neutrophils from IgAN patients produced more superoxide than those of MsPGN patients and normal controls. Conclusion: T he FMLP-activated neutrophils from patients with IgAN have differential eff ects in enhancing the cell death and the ET-1 production of glomerular mesa ngial cells through the release of superoxide. Copyright (C) 2001 S. Karger AG, Basel.