The Efficacy of CAT–152 in the Prevention of Posterior Capsular Opacification (PCO) in the Rabbit Model of Cataract Surgery and Lens Implantation

Abstract

Abstract: : Purpose:Despite advances in cataract surgical techniques and intraocular lens (IOL) implant technology, PCO remains a significant long–term complication leading to reduced vision. In–vitro studies have shown that TGF–ß plays a pivotal role in the formation of PCO and its inhibition by CAT–152 antibody reduces the lens epithelial cell (LEC) migration and myofibroblastic transformation responsible for PCO. In this study we examined whether CAT–152 given at the time of surgery influenced the development of PCO in–vivo. Methods: In a randomised, masked observer study, 37 chinchilla rabbits underwent cataract surgery, IOL implantation and an intra–operative injection (0.2ml) of either CAT–152 (200µg), null antibody (1mg) or balanced salt solution under their lens implant. Digital imaging of the posterior capsule was performed twice weekly for 10 weeks. POCOMAN software was used to quantify percentage area and severity of PCO. Results: All treatment groups developed PCO in a characteristic pattern. Initial proliferation of LECs for 10 days was followed by regression over the next 14 days. After a plateau phase of 2 weeks, maximal PCO then developed over the subsequent 4 weeks as a new wave of proliferating cells grew from the periphery. There was no difference in the severity of PCO between groups (ANOVA, p=0.247). The percentage area of PCO in the CAT–152 group showed an increased proliferation during the first phase compared to controls although it reached maximal levels at the same time (ANOVA, p=0.0062). The Kaplan–Meier survival plot, measure of fibrosis, and the mass of Sommering’s ring also showed no statistically significant differences between groups. Conclusions: A single injection of CAT–152 placed under the lens implant at the conclusions of surgery did not prevent the development of PCO. An increased initial cellular proliferation with CAT–152 consisted mostly of a monolayer of LECs with no change in eventual PCO severity. There were no adverse reactions to intraocular administration of CAT–152 in this study. The relevance of the model with respect to human adult PCO is being assessed.

Keywords: posterior capsular opacification (PCO) • treatment outcomes of cataract surgery • small incision cataract surgery