Abstract
Purpose :
Development of clinically viable imaging tools for in vivo visualization of inflammation is one of the essential tools for chorioretinal diseases including age related macular degeneration (AMD). Objective of our study was to establish the role of inflammation by virtue of labeled leukocytes in laser induced choroidal neovascularization (CNV) mouse model and to assess the impact of anti vascular endothelial growth factor (anti-VEGF) treatment on infiltrating leukocytes (leukostasis).
Methods :
B6J wild type mice were treated with laser photocoagulation to create laser induced CNV model. After exsanguination of blood from mice, leukocytes were extracted and labeled with sodium fluorescein 0.1%. Labelled leukocytes were injected through tail vein in non-lasered wild type mice (control group), laser induced CNV mice and in laser induced CNV mice treated with anti VEGF agents. Fundus fluorescein angiography (FFA), and optical coherence tomography (OCT) using scanning laser ophthalmoscopy imaging (SLO) was performed at different time interval in each group. Presence or absence of leukostasis on SLO was reported as the qualitative biomarker for inflammation and extent of inflammation on FFA was assessed quantitatively.
Results :
12 mice with age range of 8-10 weeks old were studied in groups. Presence of leukostasis was noted in study group 1 at days 4, 7, 14 and 21 post laser injury. There was presence of 80 % (SEM 2447.471, range: 109809.33 to 13498.22 pixel) area of leakage on FFA. In the laser induced CNV mice pre treated with murine anti-VEGF, there was absence of leukostasis on SLO imaging and also the area of fluorescein leakage on FFA was significantly reduced (SEM 1143.46, range: 5766 to 4248, p 0.0123). The presence of subretinal fluid (SRF) and CNV was confirmed on OCT and there was corresponding decrease in leukostasis and SRF.
Conclusions :
In animal experiments in the current study, we have demonstrated a vascular inflammation model for CNV. Role of infiltrating leukocytes and leukostasis was established in this model. Effect of anti VEGF therapy in reducing the inflammation was also demonstrated in the current study. In vivo imaging of leukostasis in CNV animal model and possibly in diabetic and uveitis animal model can be employed in future pre clinical studies for assessing the impact of emerging anti VEGF agents on inflammation.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.