Integration of Perforated Subretinal Prostheses With Retinal Tissue.

• Type of Material: Article
• Authors: Adewumi N. Adekunle, Emory University; Alice Adkins, Atlanta VA Medical Center; Wei Wang, University of Louisville; Henry J. Kaplan, University of Louisville; Juan Fernandez de Castro, University of Louisville; Sang Joon Lee, University of Louisville; Philip Huie, Stanford University; Daniel Palanker, Stanford University; Maureen McCall, University of Louisville; Machelle Pardue, Emory University
• Language: English
• Date: 2015-08
• Publisher: Association for Research in Vision and Ophthalmology (ARVO)
• Publication Version: Final Published Version
• Copyright Statement: © ARVO
• Final Published Version (URL): http://dx.doi.org/10.1167/tvst.4.4.5
• Title of Journal or Parent Work: Translational Vision Science & Technology
• ISSN: 2164-2591
• Volume: 4
• Issue: 4
• Start Page: 5
• End Page: 5
• Grant/Funding Information: Also a Research Career Scientist Award from the Department of Veterans (MTP), and a KY Research Challenge Trust Fund (HJK).; Funding was provided by the National Institutes of Health (NIH; R01-EY-018608), R01 EY14070 (MAMC), NIH HLO76138-08 (JPFdC); the Air Force Office of Scientific Research (FA9550-04); NIH CTSA (UL1 RR025744, Stanford Spectrum fund); a Stanford Bio-X IIP grant; and Research to Prevent Blindness (UofL DOVS; Emory Eye Center).
• Keywords: retinitis pigmentosa; prosthetic; migration; retina; biocompatibility
• Research Categories: Health Sciences, Opthamology; Health Sciences, Medicine and Surgery

Abstract

PURPOSE: To investigate the integration of subretinal implants containing full-depth perforations of various widths with rat and pig retina across weeks of implantation. METHODS: In transgenic P23H rhodopsin line 1 (TgP23H-1) rats and wild-type (WT) pigs, we examined four subretinal implant designs: solid inactive polymer arrays (IPA), IPAs with 5- or 10-μm wide perforations, and active bipolar photovoltaic arrays (bPVA) with 5-μm perforations. We surgically placed the implants into the subretinal space using an external approach in rats or a vitreoretinal approach in pigs. Implant placement in the subretinal space was verified with optical coherence tomography and retinal perfusion was characterized with fluorescein angiography. Rats were sacrificed 8 or 16 weeks post-implantation (wpi) and pigs 2, 4, or 8 wpi, and retinas evaluated at the light microscopic level. RESULTS: Regardless of implant design, retinas of both species showed normal vasculature. In TgP23H-1 retinas implanted with 10-μm perforated IPAs, inner nuclear layer (INL) cells migrated through the perforations by 8 wpi, resulting in significant INL thinning by 16 wpi. Additionally, these retinas showed greater pseudo-rosette formation and fibrosis compared with retinas with solid or 5-μm perforated IPAs. TgP23H-1 retinas with bPVAs showed similar INL migration to retinas with 5-μm perforated IPAs, with less fibrosis and rosette formation. WT pig retina with perforated IPAs maintained photoreceptors, showed no migration, and less pseudo-rosette formation, but more fibrosis compared with implanted TgP23H-1 rat retinas. CONCLUSIONS: In retinas with photoreceptor degeneration, solid implants, or those with 5-μm perforations lead to the best biocompatibility.