The Translocation of an Autologous Free RPE and Choroid Graft: An Experiment in Pigs

Abstract

Abstract: : Purpose: In patients with exudative age–related macular degeneration, the surgical removal of the subfoveal choroidal neovascular membrane with the subsequent translocation of an autologous midperipheral full–thickness graft of retinal pigment epithelium (RPE) and choroid under the macula is a potentially successful new treatment. This study aims to investigate whether revascularization of this graft occurs, to study the factors that influence the revascularization and survival of the graft, and to determine the morphological changes. Methods: In 9 pigs we successfully translocated a choroid–RPE–graft to an intact or intentionally damaged recipient site. We sacrificed the animals after 1 day (n = 1), 1 week (n = 4) or 3 months (n = 4) and evaluation occurred with the use of light microscopy, immunohistochemical staining and transmission electron microscopy. Results: Revascularization of the patch was identified after 1 week and 3 months, independent if the recipient had an intact or damaged Bruch’s membrane at the moment of transplantation. PAS–staining suggested that Bruch’s membrane disappeared underneath the patch. Also, the RPE–cells from the recipient layer seem to migrate into the patch, where they transform into macrophages. After one week numerous macrophages were present in the graft, and less were after 3 months. Conclusions: Revascularization of the patch occurred after translocation. The invasion of macrophages may be part of a fibrovascular wound healing response.

Keywords: age-related macular degeneration • transplantation • pathology: experimental