Abstract
Purpose: :
Subretinal transplantation of pigment epithelial cells has been advanced as a therapeutic approach for the treatment of age-related macular degeneration (AMD). However, subretinal transplantation of cell suspensions has not resulted in significant visual improvement. The transplanted cells did not form a monolayer suggesting that in AMD Bruch’s membrane is altered and does not support monolayer formation. Therefore, it may be necessary to transplant a pre-formed cell monolayer on a biodegradable substratum to re-establish the subretinal complex. Here we report on the physical and biological properties of bovine collagen as a substratum for RPE cell growth in vitro and its in vivo biocompatibility.
Methods: :
Bovine collagen type 1 membranes were stained with the fluorescent dye DTAF (Dichlorotriazinylamino-Fluorescein) to enable visualization after in vivo transplantation. ARPE-19 cell monolayers cultured on the membranes were examined for viability and morphology. The cell-membrane complex was transplanted subretinally in rabbits and monitored by fundus photography. Rabbits were sacrificed at 1, 3 and 5 weeks and the transplant area was histologically analysed to define subretinal integration, membrane degradation and inflammatory response.
Results: :
Collagen membranes were stable to manipulation and remained flat subretinally. In culture the membranes supported monolayer formation and epithelial morphology of ARPE-19 cells. Following subretinal transplantation the membranes alone integrated into the subretinal space and could be detected by fundus photography and histologically for 5 weeks with no detectable inflammatory reactions and only minor degeneration of the neurosensory retina. Transplantation of ARPE-19 cell monolayers on the collagen membranes enhanced handling and accelerated membrane degradation.
Conclusions: :
Bovine collagen membranes possess the mechanical and biological characteristics for RPE cell monolayer formation and subretinal transplantation. The enhanced degradation of the collagen membranes in the presence of cultured RPE cells suggest that the transplanted cells are metabolically active and can restructure not only the collagen membrane but also Bruch’s membrane. These properties of the collagen RPE cell monolayer complex are a promising first step in the development of a cell-based treatment of AMD.
Keywords: age-related macular degeneration • retinal degenerations: cell biology