gms | German Medical Science

Objective: Replacement of degenerated RPE cells as a therapeutic modality for AMD requires that the transplanted cells reconstitute the normal subretinal anatomy. Since transplantation of cell suspensions has not resulted in functional improvement, we hypothesize that it will be necessary to transplant cells cultured on a substratum permissive for monolayer formation with correct polarity, thus allowing communication between transplanted cells and the exposed photoreceptors. The biodegradable substrate serves as a temporary Bruch's membrane prosthesis until the transplanted cells re-assemble their native Bruch's membrane. Here we compared in vitro growth characteristics of RPE and IPE cells and in vivo biocompatibility of potential biomaterials.

Methods: ARPE-19, primary bovine RPE and IPE cells cultured on ultrathin (7μm) equine collagen type I membranes, human amniotic membranes, silk membranes and polylactic acid (PLA) electrospun nanofibers were analyzed for growth, viability and morphology. Membranes were examined for surface characteristics and permeability. Biocompatibility of these biomaterials was evaluated by subconjunctival transplantation in rabbits.

Results: Pigment epithelial cells formed monolayers on all membranes, but viability was best on collagen type I followed by amniotic membranes, polylactic nanofibers and silk membranes. Subconjunctival transplantation revealed excellent biocompatibility for the collagen and amniotic membranes. Collagen membranes show most approximate the surface morphological characteristics of Bruch's membrane.

Conclusions: Regarding the investigated substrates, collagen type I membranes are best suited as a support for pigment cells intended to be transplanted subretinally, since they support cell growth, viability and do not elicit any inflammatory reaction when transplanted subconjunctivally in rabbits.