Increased interleukin-18 content and angiogenic activity of sera from diabetic (Type 2) patients with background retinopathy.

Hyperglycaemia increases inflammatory cytokine concentration in the blood. Elevated levels of interleukin-18 (IL-18), a cytokine belonging to the interleukin-1 (IL-1) family, were recently reported in patients with Type 2 diabetes mellitus (DM2) and nephropathy. The aim of the present work was an examination of IL-18 concentration in the sera of elderly DM2 patients with nonproliferative retinopathy and age-matched control people and an estimation whether this cytokine plays pro- or anti-angiogenic role in in vivo angiogenic activity of their sera in mice cutaneous angiogenesis test. Recombinant human IL-18 injected intradermally to murine skin induced significant neovascular reaction. DM2 patients sera contained higher concentration of IL-18 and induced stronger neovascular reaction in mice skin than did the sera of corresponding control people. Sera from both groups of people after neutralization with antihuman IL-18 antibodies lost substantial part of their angiogenic activity.