Prophylactic exposure of human corneal endothelial cells to Rho-associated kinase inhibitor reduced apoptosis rate after phacoemulsification: Ex vivo study

Purpose: To evaluate whether prophylactic exposure of corneal endothelial cells (CECs) to a selective Rho-associated kinase (ROCK) inhibitor will inhibit CEC apoptosis after phacoemulsification. Setting: Laboratory evaluations at the Edith Wolfson Medical Center, Holon, Israel and the Chaim Sheba Medical Center, Tel-Hashomer, Ramat-Gan, Israel and the Chaim Sheba Medical Center, Tel-Hashomer, Ramat-Gan, Israel. Design: Experimental study. Method: Human donor corneolimbal rings were divided into fragments that were stored in commercial storage media with or without the addition of 10 mM ROCK inhibitor for 1 week and were then exposed to phacoemulsification energy. Samples were dissociated into single cells by trypsin digestion and CECs were targeted using the antihuman CD166 antibody, a new biomarker. The CEC survival was evaluated for early and late apoptosis rate with flow cytometric analysis of annexin-V and propidium iodide (PI) double staining. Results: Six corneoscleral rings from 4 donors were studied. After phacoemulsification, CEC exposed to ROCK inhibitor demonstrated a 37.06% reduction in early apoptosis rate (29.36% ± 4.33% [SD] versus 46.65% ± 1.51%, P =.006) and 45.27% reduction in late apoptosis rate (17.6% ± 16.81% versus 32.16% ± 26.30%, P =.007), compared with controls. Subsequently, ROCK levels in apoptotic CECs were significantly lower in cells incubated with ROCK inhibitor than the control medium. Conclusions: In this ex vivo study, ROCK inhibitor reduced endothelial loss and thus, could be used to limit or slow down CEC loss. Rho-associated kinase inhibitor might be used before cataract surgery, especially in high risk patients. This might be a promising new method for preventing pseudophakic bullous keratopathy.