Localized RPE Removal with a Novel Instrument Aided by Viscoelastics in Rabbits

Citation: Thieltges F, Liu Z, Brinken R, Braun N, Wongsawad W, Somboonthanakij S, Herwig M, Holz FG, Stanzel BV. Localized RPE removal with a novel instrument aided by viscoelastics in rabbits. Trans Vis Sci Tech. 2016;5(3):11, doi:10.1167/tvst. 5.3.11 Purpose: We developed a surgical method for localized and atraumatic removal of the retinal pigment epithelium (RPE) with a novel instrument. Methods: Bleb retinal detachments (bRD) were raised with balanced salt solution (BSS) following vitrectomy in 27 rabbits. The RPE was scraped with 3 loop variants (polypropylene [PP], 0.1 mm; PP, 0.06 mm; metal, 0.1 mm) of a custom-made instrument. Stabilization of bRDs with BSS or various concentrations (0.1%-0.5%) of hyaluronic acid (HA) was video analyzed. Perfusion-fixed samples of scraped areas and controls were studied by light and transmission electron microscopy. Results: The bRDs were sufficiently stabilized by 0.25% HA. Using the PP 0.1 mm loop with a single forward/backward stroke, an area of ca. 2.5 3 1.5 mm was nearly devoid of RPE, yet did show occasional Bruch's membrane (BM) defects combined with choriocapillaris hemorrhages in 13% of the bRDs. A single scrape with PP 0.06 mm resulted in unsatisfactory RPE denudement, while repeated scraping maneuvers caused more BM defects and hemorrhages. The metal loop resulted in incomplete RPE removal and massive intraoperative subretinal hemorrhages. Histologically, intact photoreceptor outer segments (POS) were observed above the RPE wounds in bRDs. Controls with bRDs alone showed an intact RPE monolayer with microvilli, with few engulfed remains of POS. Conclusions: Localized removal of RPE in HA stabilized bRD can be achieved by a PP 0.1 mm loop instrument. Translational Relevance: Removal of degenerated RPE may aid RPE cell replacement strategies

Subretinal Delivery of Ultrathin Rigid-Elastic Cell Carriers Using a Metallic Shooter Instrument and Biodegradable Hydrogel Encapsulation

10.1167/iovs.11-8260INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE531490-50

Localized RPE Removal with a Novel Instrument Aided by Viscoelastics in Rabbits

10.1167/tvst.5.3.11TRANSLATIONAL VISION SCIENCE & TECHNOLOGY5

A Step by Step Protocol for Subretinal Surgery in Rabbits

10.3791/53927JOVE-JOURNAL OF VISUALIZED EXPERIMENTS201611

Human RPE Stem Cells Grown into Polarized RPE Monolayers on a Polyester Matrix Are Maintained after Grafting into Rabbit Subretinal Space

Transplantation of the retinal pigment epithelium (RPE) is being developed as a cell-replacement therapy for age-related macular degeneration. Human embryonic stem cell (hESC) and induced pluripotent stem cell (iPSC)-derived RPE are currently translating toward clinic. We introduce the adult human RPE stem cell (hRPESC) as an alternative RPE source. Polarized monolayers of adult hRPESC-derived RPE grown on polyester (PET) membranes had near-native characteristics. Trephined pieces of RPE monolayers on PET were transplanted subretinally in the rabbit, a large-eyed animal model. After 4 days, retinal edema was observed above the implant, detected by spectral domain optical coherence tomography (SD-OCT) and fundoscopy. At 1 week, retinal atrophy overlying the fetal or adult transplant was observed, remaining stable thereafter. Histology obtained 4 weeks after implantation confirmed a continuous polarized human RPE monolayer on PET. Taken together, the xeno-RPE survived with retained characteristics in the subretinal space. These experiments support that adult hRPESC-derived RPE are a potential source for transplantation therapies

Human RPE Stem Cells Grown into Polarized RPE Monolayers on a Polyester Matrix Are Maintained after Grafting into Rabbit Subretinal Space

10.1016/j.stemcr.2013.11.005STEM CELL REPORTS2164-7