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Bibiana Iglesias, Carmelo Romano; Effect of triamcinolone in a rabbit model of sustained retinal neovascularization and leak.. Invest. Ophthalmol. Vis. Sci. 2019;60(9):3669. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Corticosteroids block vascular permeability by affecting a wide range of cellular processes such as VEGF and adhesion molecule expression. The steroid triamcinolone has been approved by the FDA to be used in the treatment of diabetic and CRVO associated macular edema. In rabbits, triamcinolone is capable of preventing VEGF-induced vascular permeability and morphological vascular changes. To study the effects of triamcinolone in a chronic pathological neovascularization rabbit model, we tested whether triamcinolone was able to revert the pathological leak and neovascular growth induced by intravitreal injection of DL-alpha-aminoadipic acid (DL-AAA)1. In rabbits, DL-AAA promotes sustained retinal neovascularization and leak. In these rabbits, VEGF blockade not only suppresses vascular permeability in a dose dependent manner but also induces regression of the pathological vessels.1. Cao et al., ARVO 2017
Male New Zealand White rabbits (2.0-2.5 kg) received intravitreal DL-AAA. After 25 weeks and following an eye examination, rabbits were divided into 2 treatment groups: placebo or Triesence (triamcinolone acetonide). The placebo animals received 50 ul of formulation buffer while the Triesence animals received 2 mg of triamcinolone in 50 ul. Red free imaging (RF), fluorescein angiography (FA) and optical coherence tomography (OCT) were performed weekly after treatment (weeks 1 through 5). Vascular morphological changes were assessed based on the RF images and vascular permeability was calculated by measuring fluorescein leak area on the angiogram images.
Treatment with triamcinolone partially suppressed vascular leak in DL-AAA eyes. However, triamcinolone’s effects on pathological vasculature regression of DL-AAA eyes were minimal.
In the DL-AAA rabbit model of retinal neovascularization, triamcinolone was not effective at completely blocking vascular permeability or reducing pathological vascular changes, when compared to aflibercept. This result suggests that steroids, while able to suppress some VEGF-dependent vascular pathologies, are not able to revert all.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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