Objectives: Studies were performed to develop a prolonged antiangiogenesis therapy regimen based on theranostic ανβ3-targeted nanoparticles. Background: Antiangiogenesis therapy may normalize atherosclerotic plaque vasculature and promote plaque stabilization. ανβ3-targeted paramagnetic nanoparticles can quantify atherosclerotic angiogenesis and incorporate fumagillin to elicit acute antiangiogenic effects. Methods: In the first experiment, hyperlipidemic rabbits received ανβ3-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 ανβ3-targeted paramagnetic nanoparticles. In a second 8-week study, atherosclerotic rabbits received atorvastatin (0 or 44 mg/kg diet) alone or with ανβ3-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 ανβ3-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 ανβ3-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 ανβ3-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 ανβ3-targeted nanoparticles were constrained to the vasculature of the aortic adventia. Conclusions: The CMR molecular imaging with ανβ3-targeted paramagnetic nanoparticles demonstrated that the acute antiangiogenic effects of ανβ3-targeted fumagillin nanoparticles could be prolonged when combined with atorvastatin, representing a potential strategy to evaluate antiangiogenic treatment and plaque stability.
- molecular imaging