Interleukin-18/Interleukin-18 Binding Protein Signaling Modulates Ischemia-Induced Neovascularization in Mice Hindlimb

Abstract

Identification of factors that may stimulate ischemia-induced neovascularization without increasing atherosclerotic plaque progression is of major therapeutic importance. We hypothesized that interleukin-18 binding protein (IL-18BP), a major antiinflammatory protein with plaque-stabilizing activities, may affect the neovascularization in mice ischemic hindlimb. Ischemia was produced by artery femoral occlusion in mice that were subjected to in vivo intramuscular electrotransfer of either an empty plasmid or a murine IL-18BP plasmid. Angiographic score, capillary density (CD31 staining), and laser Doppler perfusion data at day 28 showed significant improvement in ischemic/nonischemic leg ratio by respectively 1.6-, 1.4-, and 1.5-fold in IL-18BP–treated mice compared with controls (PPP<0.001). In conclusion, IL-18BP stimulates ischemia-induced neovascularization in association with an activation of VEGF/Akt signaling and an increase in BM-EPCs mobilization and differentiation. Our findings strongly suggest a major antiangiogenic role of endogenous IL-18 in postischemic injury.