Abstract
Purpose :
Blebs from bleb-forming glaucoma surgeries utilize sub-conjunctival lymphatics for aqueous outflow and intraocular pressure (IOP) reduction. Here, we test the ability to pharmacologically manipulate sub-conjunctival lymphatic presence as a way to modulate bleb biology.
Methods :
Lymphatics are natively visible in reporter mice that express GFP under a Prox-1 promoter. Sub-conjunctival injection was performed for various agents (vascular endothelial growth factor-C [VEGFC; 6 eyes, 0.36 mg/ml], mitomycin-C [MMC; 4 eyes, 0.4 mg/ml] and 5-fluorouracil [5FU; 4 eyes, 50 mg/ml]) or control (PBS; 2 eyes). Three sub-conjunctival injections were given (every other day), and eye were harvested and fixed in 4% PFA on the 7th day. Anterior segment flat mounts were created and visualized under fluorescent microscopy. Sub-conjunctival lymphatic presence was quantitated assessing lymphatic length and number of branch points per quadrant.
Results :
Sub-conjunctival lymphatics are readily visible in control conditions. After sub-conjunctival injection of various agents, alterations to sub-conjunctival lymphatics showed a significant increase in lymphatic length and branching comparing VEGFC to control (Length: VEGFC= 436 +/- 17; control=254 +/- 17 microns; VEGFC vs control p <0.001 (Branching: VEGFC=13+/-3.9; control=7.5+/-1.2 branches; VEGFC vs control p=0.05. There was also a significant decrease in lymphatic length and branching comparing MMC to control (Length: MMC= 157+/- 35; control=254 +/- 17 microns; MMC vs control p =0.02) (Branching: MMC=3.75+/-1.5; control=7.5+/-1.2 branches; MMC vs control p =0.02). There was no difference in lymphatic length and branching comparing 5FU to control (Length: 5FU= 277 +/- 17; control=254 +/- 17 microns; 5FU vs control p=0.35) (Branching: 5FU=9+/-1.0; Control=7.5+/-1.2 branches; 5FU vs control p=0.22).
Conclusions :
Sub-conjunctival lymphatic presence can be pharmacologically manipulated. Enhanced presence may be useful for improving aqueous outflow and IOP reduction after performing bleb-forming glaucoma surgeries. Limiting sub-conjunctival lymphatic presence may improve the sub-conjunctival space as a drug delivery depot by diminishing lymphatic drainage from that space.
This is a 2020 ARVO Annual Meeting abstract.