Inhibition of vascular endothelial growth factor-mediated neointima progression with angiostatin or paclitaxel

PURPOSE: Therapeutic angiogenesis represents a new paradigm for treatment of ischemic vascular syndromes. However, vascular endothelial growth factor (VEGF) enhances the rate and degree of plaque formation. This study evaluates the potential to block these effects nonspecifically with paclitaxel or specifically with angiostatin. MATERIALS AND METHODS: Recombinant human VEGF₁₆₅ (rhVEGF) was administrated intramuscularly (2-μg/kg single injection) in combination with adventitial delivery of paclitaxel, angiostatin, or vehicle alone at the site of femoral arterial balloon overdilation injury in New Zealand White rabbits (n = 5 per treatment). Five additional animals with no rhVEGF and no adventitial delivery served as procedural controls. All rabbits were fed according to a 0.25% cholesterol diet beginning 28 days before angioplasty. Treated arteries were harvested after 7 days and evaluated to determine intima-to-media (I/M) ratios, macrophage infiltrate, and endothelial cell density. RESULTS: On histologic analysis, the rhVEGF/gel control group exhibited a mean I/M ratio of 0.337 ± 0.028, a 77% increase over procedural controls, which exhibited a mean I/M of 0.190 ± 0.010. rhVEGF/paclitaxel reduced I/M ratios to 0.151 ± 0.007. In contrast, specific antiangiogenic therapy (rhVEGF/angiostatin) reduced I/M ratios to 0.032 ± 0.003, a 91% decrease relative to rhVEGF/gel and an 83% decrease relative to procedural controls (P = .001 for each comparison). Local macrophages and endothelial cells also decreased with treatment. CONCLUSIONS: This study shows that paclitaxel and angiostatin each afford local protection against rhVEGF-mediated increases in neointima. Angiostatin further prevents progression of underlying neointima. These local therapies may allow broader use of therapeutic angiogenesis while avoiding and treating potentially undesirable effects.