Abstract
Abstract: :
Purpose: The Royal College of Surgeons (RCS) rat undergoes a progressive loss of photoreceptors due to a retinal pigment epithelial (RPE) cell defect. We examined whether healthy human derived RPE (hRPE) cells (cell line ARPE19) would preserve rod and cone function when injected subretinally at age P23 prior to significant degeneration. Methods: Animals with subretinal hRPE and sham injections were examined longitudinally with full field corneal electroretinogram (ERG) at ages P60, 90 and 120. Results: At P60, dark–adapted ERGs from hRPE injected eyes showed preserved a–waves (33 ± 6 µV vs none in sham injected eyes), mixed b–waves (136 ± 36 µV vs 15 ± 9 µV), oscillatory potentials (158 ± 32 µV vs none) and double flash isolated rod b–waves (108 ± 17 µV vs 11 ± 3 µV) and cone b–waves (63 ± 16 µV vs 20 ± 5 µV). Maximal mixed b–wave amplitudes were obtained at –0.02 log cds/m2, showing reductions at higher stimulus luminance (up to 2.8 log cds/m2). Cone b–waves remained stable after maximal amplitudes were reached. Photopic ERGs showed preserved b–waves (43 ± 9 µV vs 15 ± 8 µV) and critical flicker fusions of 27 ± 4 Hz vs 14 ± 2 Hz. Preserved ERG responses persisted up to P120 but were highly dysfunctional. Conclusions: Subretinal injections of human RPE cells in dystrophic RCS rats can preserve rod and cone ERG, but with time responses deteriorate despite the anatomical persistence of photoreceptors.
Keywords: electroretinography: non-clinical • degenerations/dystrophies • transplantation