Inhibitory effect of an antibody to cryptic collagen type IVepitopes on choroidal neovascularization

[摘要] Purpose: The wet form of age-related macular degeneration (AMD)occurs as a consequence of abnormal blood vessel growth from the choroidinto the retina. Pathological angiogenesis during tumor growth andocular disease has been associated with specific exposure of crypticextracellular matrix epitopes. We investigated the presence of crypticcollagen IV epitopes in a murine model of choroidal neovascularization(CNV), and tested the effect on blood vessel growth of H8, a humanizedantibody directed against a cryptic collagen type IV epitope.Methods: To induce experimental CNV in adult C57BL/6 mice, Bruch'smembrane was ruptured using a diode laser. Subsequently, mice weretreated with daily intraperitoneal (i.p.) injections of either H8 (10mg/kg or 30 mg/kg) or an isotype-matched antibody control. Two weekspostinjection, choroidal flat mounts were immunostained with the bloodvessel marker platelet/endothelial cell adhesion molecule-1 (PECAM-1)and H8. CNV was visualized using fluorescence microscopy and the CNVlesion area measured using Open Lab software.Results: Collagen type IV and the cryptic epitope were observed atthe site of laser-induced lesions. Staining with H8 was first observedthree days post injury, two days after MMP2 expression in CNV lesions,becoming most intense five days following laser injury and extendingbeyond the area of neovascularization. At 14 days post injury, H8staining was reduced in intensity, colocalized with the area of CNV, andwas nearly absent from the underlying choroidal vessels. In addition,mice treated with H8 had a significant dose-dependant decrease in thearea of CNV as compared to isotype-matched antibody controls.Conclusions: Results suggest that exposure of cryptic collagen typeIV epitopes is associated with the incidence of CNV and that thehumanized antibody H8 may provide a new treatment for CNV.

[学科分类] 生物化学/生物物理