Abstract
Purpose :
Clinical studies suggest that RPE transplant may delay geographic atrophy progression in AMD patients. Our purpose is to examine a novel device for a novel soft monolayer RPE sheet implantation to the subretinal space in a domestic pig in an in vivo study.
Methods :
A novel RPE implant comprised of natural biocompatible scaffold with a printed monolayer of polygonal RPE cells was developed. Implants demonstrate high viability, density, morphology, identity to RPE markers such as PMEL17 and potency by measuring PEDF secretion. For safe delivery of the RPE implant into the subretinal space a novel delivery device has been developed. A patented safe folding of the RPE implant into the device allows to transplant a 2x4 mm RPE implant through a standard 20G trocar. In order to insert the RPE implant into the subretinal space a 25G pars plana vitrectomy performed followed by a retinal bleb formation using a 41G canula. A 25G trocar replaced by a 20G trocar, the device is inserted into the subretinal space and the 2x4 mm RPE implant is released, followed by flattening the retina. Animals were followed for eight weeks, during which, OCT imaging and clinical examination took place.
Results :
A total of six eyes of six female domestic pigs were included in this prospective study. Four study eyes underwent subretinal RPE transplant (two with systemic and topical immunosuppression and two with short systemic and full topical immunosuppression) and two control eyes (underwent the procedure without RPE transplant). At the end of the follow up period, all eyes were without inflammation signs, retinas were attached with normal neuroretinal layers and without evidence of proliferative vitro retinopathy, intraretinal nor subretinal fluid nor photoreceptor atrophy on OCT. At the end of the follow up period four eyes had clear crystalline lenses and two eyes developed significant cataract.
Histopathological examination demonstrated the presence of human RPE cell monolayer, with no immune cell activity.
Conclusions :
A subretinal transplant of a novel printed RPE sheet implant with the aid of a novel 20G delivery device may be a safe method for RPE subretinal transplantation.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.