Antiangiogenic Synergism of Integrin-Targeted Fumagillin Nanoparticles and Atorvastatin in Atherosclerosis

Objectives: Studies were performed to develop a prolonged antiangiogenesis therapy regimen based on theranostic α_νβ₃-targeted nanoparticles. Background: Antiangiogenesis therapy may normalize atherosclerotic plaque vasculature and promote plaque stabilization. α_νβ₃-targeted paramagnetic nanoparticles can quantify atherosclerotic angiogenesis and incorporate fumagillin to elicit acute antiangiogenic effects. Methods: In the first experiment, hyperlipidemic rabbits received α_νβ₃-targeted fumagillin nanoparticles (0, 30, or 90 μg/kg) with either a continued high fat diet or conversion to standard chow. The antiangiogenic response was followed for 4 weeks by cardiac magnetic resonance (CMR) molecular imaging with α_νβ₃-targeted paramagnetic nanoparticles. In a second 8-week study, atherosclerotic rabbits received atorvastatin (0 or 44 mg/kg diet) alone or with α_νβ₃-targeted fumagillin nanoparticles (only week 0 vs. weeks 0 and 4), and angiogenesis was monitored with CMR molecular imaging. Histology was performed to determine the location of bound nanoparticles and to correlate the level of CMR enhancement with the density of angiogenic vessels. Results: The α_νβ₃-targeted fumagillin nanoparticles reduced the neovascular signal by 50% to 75% at 1 week and maintained this effect for 3 weeks regardless of diet and drug dose. In the second study, atherosclerotic rabbits receiving statin alone had no antineovascular benefit over 8 weeks. The α_νβ₃-targeted fumagillin nanoparticles decreased aortic angiogenesis for 3 weeks as in study 1, and readministration on week 4 reproduced the 3-week antineovascular response with no carry-over benefit. However, atorvastatin and 2 doses of α_νβ₃-targeted fumagillin nanoparticles (0 and 4 weeks) achieved marked and sustainable antiangiogenesis. Microscopic studies corroborated the high correlation between CMR signal and neovessel counts and confirmed that the α_νβ₃-targeted nanoparticles were constrained to the vasculature of the aortic adventia. Conclusions: The CMR molecular imaging with α_νβ₃-targeted paramagnetic nanoparticles demonstrated that the acute antiangiogenic effects of α_νβ₃-targeted fumagillin nanoparticles could be prolonged when combined with atorvastatin, representing a potential strategy to evaluate antiangiogenic treatment and plaque stability.