Expression of Transforming Growth Factor–b2 Following Sclerostomy and ExPRESS R Glaucoma Drainage Implant Beneath a Scleral Flap in a Rabbit Model.

Abstract

Abstract: : Purpose: Transforming Growth Factor–b2 (TGFb2) is elevated following surgery and has been shown to enhance fibrosis and increase the risk of bleb failure. Clinically, eyes undergoing ExPress shunt implantation have anecdotally been noted to look less inflamed in the early post–operative period. This study was designed to determine whether placement of an ExPress glaucoma drainage shunt underneath a scleral flap at the time of filtration surgery excites less TGFb2 formation in the bleb tissues post–operatively compared to standard filtration surgery Methods: One eye of 20 NZW rabbits was randomly selected for either a standard sclerostomy filtration surgery procedure or implantation of an ExPress drainage shunt beneath a partial thickness scleral flap. Conjunctival, Tenon’s capsule and scleral tissues were harvested from the bleb site 5 days after the surgery and levels of TGFB2 measured by ELISA. Tissues 180⁰ from the bleb were also harvested to serve as a control. Results: Significantly higher levels of TGFB2 were detected in the bleb tissues of the eyes that underwent a sclerostomy filtration procedure (mean of 150 pg/mg tissue) than with the ExPress shunt under the scleral flap (mean 70 pg/mg tissue). Conclusions: The ExPress shunt filters induced less increase in TGFb2 post–operatively and this may reduce the risk of bleb failure and/or decrease the need for anti–scarring therapy.

Keywords: growth factors/growth factor receptors • wound healing