Abstract
Purpose: :
Intravitreal bevacizumab has become a successful treatment option for choroidal neovascular disease and is now being considered as an adjuvant treatment of rubeosis iridis, e.g. in neovascular glaucoma. For this purpose the intravitreal as well as intracameral application mode is in use, without a definite guideline which technique is superior. The aim of our study was to locate the antibody bevacizumab in the tissues of the anterior segment related to neovascularization within 1-14 days after intravitreal injection in the primate eye.
Methods: :
1.25 mg bevacizumab were injected into the vitreous of 4 Cynomolgus monkeys. The eyes were enucleated on day 1, 4 and 14 for immunohistochemistry, using donkey anti-human Cy3-IgG. Untreated control eyes were stained in the same way.
Results: :
Bevacizumab was localized in the blood vessels walls of the iris, anterior chamber angle and ciliary body after intravitreal injection. The stroma was stained less intense. In the iris and chamber angle the most prominent immunoreactivity was seen on day 1 after injection and decreased up to day 14. In the ciliary body staining for bevacizumab was most intense on day 4, with only little attenuation until day 14. Some, but not all vessel lumens showed positive immunoreactivity. This finding was seen particularly in the ciliary body and the iris on day 4 and 14. There was no immunoreactivity in the negative controls.
Conclusions: :
Intravitreal injection of bevacizumab leads to a quick penetration of the antibody into the iris, anterior chamber angle and ciliary body of the primate eye. Bevacizumab preferentially accumulates in the blood vessel walls. Whereas in the iris and anterior chamber angle the highest concentration is present on day 1 after injection, the peak concentration for the ciliary body is seen on day 4. This finding is in accordance with the clinically observed rapid disappearance of iris and chamber angle neovascularization after intravitreal injection of bevacizumab.
Keywords: neovascularization • iris • anterior segment