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WonKyung Cho, Sharad Mittal, Elsayed Elbasiony, Sunil Chauhan; Novel function of ocular surface mast cells in promoting corneal angiogenesis. Invest. Ophthalmol. Vis. Sci. 2020;61(7):2321.
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© ARVO (1962-2015); The Authors (2016-present)
Corneal neovascularization, induced by various ocular insults, compromises corneal transparency. The present study investigated the function of ocular surface mast cells in mediating corneal angiogenesis following ocular injury in a murine model of corneal angiogenesis.
Distribution of mast cells at the ocular surface was evaluated by immunohistochemistry (IHC) analysis of avidin stained corneas of balb/c mice. Neovascularization was induced by placing a single figure-8 intrastromal suture on the nasal side of the cornea using 11-0 nylon suture. Mast cell activation was evaluated by quantifying mast cell specific β-tryptase and β-hexosaminidase levels in the tear wash. Vessel growth was clinically evaluated using slit lamp. Corneas were harvested and stained for CD31+ (vascular endothelial cell marker) for IHC analysis of microvascular angiogenesis. Mice were locally treated with mast cell blocker (2% cromolyn in PBS) to study the effect of mast cell inhibition on angiogenesis.
Immunohistochemistry analysis demonstrated abundance of mast cells in peripheral cornea and limbal area. Tear wash collected at 0, 3, 6 hours following intrastromal suture placement showed a significant 5-fold increase of tryptase (p<0.01) and a 2-fold increase in β-hexosaminidase levels, relative to naive controls. Significant neovascularization towards the site of suture placement was observed by day 4 post-surgery (3.6 ± 0.4% vs. 16.2 ± 1.6%; p<0.01). Treatment of cromolyn, a mast cell inhibitor, abated angiogenesis as observed under the slit lamp (12.4 ± 2.3% vs. 5.6 ± 0.03%; p<0.05). This effect was further confirmed with CD31+ IHC analysis demonstrating a significantly smaller vascular area compared to PBS-treated control (1.5 ±0.2 mm2 vs. 0.5 ± 0.02 mm2; p<0.01).
Our data demonstrate that blockade of ocular surface mast cell activation inhibits neovascularization, suggesting mast cells contribute to corneal angiogenesis.
This is a 2020 ARVO Annual Meeting abstract.
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