Dissection and cotransplantation of large pieces of RPE and neural retina; effect of protease K on the development

Abstract

ABSTRACT.Purpose: This study attempts to cotransplant large pieces of the RPE and neural retina in the subretinal space of rabbits by using protease K for dissection of the donor tissue, and to investigate the effect of dissection technique on the development of the grafts. Methods: Eyes from 15-day-old pigmented rabbit embryos were partly digested by protease K to assist dissection of sclera and the choroid from RPE and neural retina. Large pieces of RPE and the neural retina thus obtained were cotransplanted into the eyes of adult albino rabbits who were allowed to survive for up to 63 days. The transplants were examined under light microscope. Results: It was possible to transplant large sheets of RPE and neural retina together. Both the RPE and the neural retina survived after cotransplantation. Retinal pigment epithelium survived in layers, but at places formed clusters. In cotransplants neural retina formed rosettes, developed gliosis, and photoreceptors failed to develop outer segments, possibly due to the action of protease K. Conclusion: Proteases seem to be injurious for the development of the neural retina.

Adeno-Associated Virus Encoding Green Fluorescent Protein as a Label for Retinal Pigment Epithelium

“…One of the earliest and easiest methods used to identify transplanted RPE cells was pigmentation (i.e., transplantation of pigmented RPE cells into recipients who had no pigmented RPE). 6,12,[23][24][25][26][27][28] Although this method may be suitable for short-term studies, release of pigment into the subretinal space 26 and subsequent phagocytosis of pigment by native RPE cells 29,30 prevents unambiguous identification of the transplanted cells. In addition, RPE cells lose their pigment with cell division.…”

Transplantation Frontiers

“…255,296 Both preparations often form spherical structures or rosettes, with photoreceptors oriented towards a central lumen similar to those seen in retinoblastomas and retinal dysplasias. 297 In addition, both retinal microaggregates and cell suspensions frequently are contaminated with non-photoreceptor retinal cells. 297 In addition, both retinal microaggregates and cell suspensions frequently are contaminated with non-photoreceptor retinal cells.…”

“…263,264 Several growth factors, neurotrophic factors, and cytokines such as basic fibroblast growth factor (bFGF), acidic fibroblast growth factor (aFGF), CNTF, GDNF, BDNF, and IL-1β have been shown to exert robust survivalpromoting effects in the retina when injected subretinally or intravitreally, 250,305 or when delivered by adenovirus gene therapy 306 in various animal models of retinal degeneration. 118,258,[315][316][317][318] This work has documented the feasibility of retinal transplantation, with long-term survival of the transplant in both animals 286,297 and humans. 312,313 This effect is probably mediated by injury-induced upregulation of neurotrophic factors.…”

Preconditioning protects the retinal pigment epithelium cells from oxidative stress‐induced cell death

“…2005). RPE cell transplantation aims at replacing the dysfunctional cells and has shown promising results in animal models (Sharma & Ehinger 1999; Sharma 2000). However, in the clinical situation, transplanted cells must thrive in vivo , in spite of the fact that the original conditions – including the oxidative stress that caused the initial RPE damage – are still in place.…”