Inhibitory Effects of Angiotensin II Receptor Blockade on Human Tenon Fibroblast Migration and Reactive Oxygen Species Production in Cell Culture

Purpose: We investigate the effect of angiotensin receptor blockade on the migration of human Tenon fibroblasts (HTF), using irbesartan, an angiotensin II receptor type 1 (AT1R) blocker (ARB) as a potential antifibrotic agent in glaucoma filtration surgery. Methods: Confluent HTF cultures were scratched with a 1 mL pipette tip and treated with either irbesartan (10, 50, and 100 mu g/mL) or angiotensin II (2 mu g/mL). The extent of HTF migration up to 30 hours, and cell number and morphology at 72 hours was evaluated. To assess the effect on reactive oxygen species (ROS) level, HTF were treated with either irbesartan (10 mu g/mL) or angiotensin II (2 mu g/mL) for 24 hours after scratching, and then stained with dihydroethidium (DHE) before evaluation by confocal microscopy. Results: Irbesartan inhibited HTF migration by 50% to 70% compared to controls (P < 0.05). Levels of ROS were almost completely attenuated by irbesartan (DHE fluorescence intensity of 5.68E-09) (P < 0.05). Irbesartan reduced cell numbers by 50% and induced morphologic changes with loss of pseudopods (P < 0.05). Conversely, angiotensin II increased cell numbers up to 4-fold while retaining cell viability. Conclusions: Irbesartan inhibited HTF migration and ROS production. It also reduced cell numbers and altered HTF morphology. Angiotensin II increased cell number without altering morphology. This initial study warrants future investigations for further potential antifibrotic effects of this drug.