Serum angiostatin and endostatin levels in patients with granulomatosis with polyangiitis and immune complex small vessel vasculitis

OBJECTIVES: Inflammation has been revealed to be associated with angiogenesis. Granulomatosis with polyangiitis (GPA) and immune complex small vessel vasculitis (ICSVV) are forms of systemic vasculitides of different pathogenesis. GPA is a necrotizing granulomatosis and ICSVV is associated with inflammation of postcapillary venules induced by deposits of immune complexes. The aim of the study was to determine serum levels of angiostatin and endostatin, natural angiogenesis inhibitors, in patients with GPA and ICSVV as well as healthy individuals. MATERIAL AND METHODS: Two groups of patients with GPA (20 patients) and ICSVV (20 patients) as well as 20 controls were investigated. All patients were investigated before initiation of immunosuppressive therapy or administration of corticosteroids. Angiostatin and endostatin levels were assayed with the ELISA method. RESULTS: Enhanced serum levels of angiostatin and endostatin were found in patients with GPA but not in those suffering from ICSVV. In patients with GPA increased levels of angiogenesis inhibitors correlated with the disease activity. A correlation between angiostatin and endostatin levels was observed in all groups of investigated individuals. CONCLUSIONS: It is suggested that formation of necrotizing granulation is associated with profound activation of angiogenesis and an increase in serum levels of inhibitors is a phenomenon occurring during blood vessel formation in the granulation tissue. The obtained results confirm involvement of angiogenesis in pathogenesis of at least some forms of vasculitides and suggest the need for continuation of investigations in this field.