Abstract
Purpose :
To investigate the involvement of the LTB4 pathway in EAU disease progression.
Methods :
To induce EAU, female C57Bl/6 mice, aged 5-8 weeks, were immunized with IRBP1-20 (Cortes LM et al, 2008). At different time points post immunization, vitreous fluids (5-10 µL) were extracted and assayed for LTB4 levels by ELISA (R&D systems). Chemically synthesised LTB4 (C20H32O4; 100 pM) was intravitreally introduced (1-2 µL) into healthy mice and changes to the retina/choroid were monitored by retinal fundoscopy and angiography at different time points post immunization. EAU disease progression was graded clinically when mice were intravitreally treated by the LTB4-specific inhibitor, L-nomacopan, a recombinant protein derived from the saliva of blood-feeding ticks.
Results :
A significantly increased level of LTB4 was detected (30-200 pg/mL; P<0.03) in 19 vitreous fluids extracted from two eyes per mouse (n=30) at different stages of disease relative to controls (day 5, 39.4±10.9 pg/mL, n=7, P=0.03; day 12, 98.4±40.88 pg/mL, n=9, P=0.044). We also found that introducing LTB4 intravitreally induced an observed increase in vascular permeability and recruitment of myeloid cells (CD11b, CD11c, Ly.6c) into the vitreoretinal space. Targeting LTB4 by intravitreal L-nomacopan inhibited vascular permeability and suppressed disease progression as monitored. We are currently investigating LTB4 levels and their correlation with clinical features (vessel cuffing, tissue inflammation and damage).
Conclusions :
Using in vivo models, LTB4 plays an important role during disease progression and specific inhibitors can mitigate EAU progression in a therapeutic approach.
This is a 2020 ARVO Annual Meeting abstract.