Inhibition of inflammatory corneal angiogenesis by TNP-470.

PURPOSE: To determine the efficacy of the angiogenic inhibitor TNP-470 on inflammatory corneal neovascularization. Topical and systemic delivery of the drug were investigated in a murine model as well as inhibition of endothelial cell proliferation in vitro and in vivo.

METHODS: The effect of TNP-470 on VEGF- and bFGF-stimulated bovine capillary endothelial (BCE) cell proliferation was evaluated in vitro. Corneal neovascularization was induced in vivo by mechanical debridement of the corneal and limbal epithelium with 0.15 M NaOH on C57BL6 mice. TNP-470 was administered systemically at 30 mg/kg body weight (BW) every other day or topically three times daily in a concentration of 5 ng/ml dissolved in methylcellulose. Vessel length was investigated on day 7. VEGF protein content in murine corneas was analyzed by ELISA on days 2, 4, and 7 of treatment. A modified bromouridine (BrdU) ELISA was used to quantify endothelial cell proliferation.

RESULTS: TNP-470 exerted a dose-dependent inhibition of bFGF- and VEGF-induced endothelial cell proliferation in vitro. Both systemic and topical application of TNP-470 led to a significant reduction of inflammatory corneal neovascularization (P < 1 x 10(-5)). BrdU labeling showed that TNP-470 inhibited endothelial cell proliferation. VEGF protein levels were reduced by systemic TNP-470 treatment.

CONCLUSIONS: These results suggest that TNP-470 reduces inflammatory corneal angiogenesis by directly inhibiting endothelial cell proliferation. Topical and systemic treatment with TNP-470 reduces VEGF levels that are responsible for vessel growth during the neovascularization process.