Abstract
Purpose :
Ocular fibrosis is not only a chronic process responsible for the pathogenesis or treatment failure of many blinding eye diseases but also one of the important causes of irreversible visual impairment in patients. CNV-related subretinal fibrosis in age-related macular degeneration (AMD), fibrovascular membranes in diabetic retinopathy (DR), proliferative vitreoretinopathy (PVR) and epiretinal membranes (ERM) may limit the long-term visual prognosis of affected patients. To date, only very limited successful treatment for ocular scarring exists. We aim to investigate the impact of anti-fibrotic compounds on ocular fibrosis. Therefore we examined in a time-dependent subretinal fibrosis animal model the effect of rho-kinase (ROCK) isoform specific inhibition on ocular fibrosis.
Methods :
To induce CNV-related fibrosis, we used a 532-nm laser inserted in a slit-lamp delivery system. After the development of fibrosis on day 35, 8-9 week old mixed gender C57BL/6 mice were treated intraperitoneally every day with fasudil ( pan ROCK inhibitor ) or belosumodil ( ROCK2 inhibitor ) for two weeks. We performed optical coherence tomography (OCT), autofluorescence and fluorescence angiography every week after laser injury ( d7,14,21,28,35,42,49, n=6 mice per timepoint ) to document fibrotic changes over time. In addition, we screened choroidal flat mounts, western blot and eye sections for CNV and fibrosis.
Results :
From day 21 to day 49 after laser injury of mice eyes CNV and leakage decreased and subretinal fibrosis increased in OCT and fluorescence angiography. The expression of type 1 collagen in lesions of choroidal flat mounts increased, whereas isolectin B decreased. CNV reaches a maximum on days 7 to 14, after which it regresses and almost completely disappears from 21 to 35 days post-laser when fibrosis increases. After treatment, fibrosis volume decreased, and both ROCK inhibitors substantially reduced subretinal fibrosis in vivo. In addition, type 1 collagen in flatmounts and western blot of the RPE-choroid complex decreased with ROCK inhibition.
Conclusions :
The current results indicate that rho-kinase might play a role in ocular fibrosis. The ROCK inhibitors fasudil and belosumodil may have therapeutic potential for the treatment of subretinal fibrosis in neovascular age-related macular degeneration and other ocular scarring diseases.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.