Purpose Photoreceptor loss due to retinal degenerative diseases or injury is the leading cause of untreatable blindness. Replacement of photoreceptors has been suggested as a potential therapeutic approach for treatment of retinal degenerative diseases, such as retinitis pigmentosa and age-related macular degeneration. Here we report the primary results of transplantation of human retinal progenitor cells (hRPCs) into the subretinal space of retinal degenerative mice.
Methods hRPCs were isolated from 12-18 wk gestational age retina and expanded in vitro. Cells were characterized by immunohistochemistry for expression of progenitor markers. 100,000 live cells were transplanted into the subretinal space of rhodopsin -/- mice in HBSS. Mice in control group received subretinal injection of HBSS. Electroretinogram (ERG) and optical coherence tomography (OCT) were performed at various time after transplantation. Mice were sacrificed by CO2 inhalation 4 to 8 weeks after transplantation. Immunohistochemistry study was performed with the following primary antibodies against human mitochondria, nestin, Ki67, rhodopsin, recoverin. Retinal sections were viewed on a confocal microscope.
Results 4 to 8 weeks after transplantation, a subset of hRPCs survived as xenografts in the mouse subretinal space without exogenous immunosuppression. The OCT results confirmed that the transplanted hRPCs resided in the subretinal space. A subpopulation of Grafted hRPCs migrated and incorporated into the recipient neural retina as was confirmed by human mitochondria staining. A few of integrated cells also express photoreceptor markers rhodopsin and recoverin. The ERG results showed no significantly differences between the hRPC treatment group and HBSS control group.
Conclusions hRPCs survive in the mouse retina without immunosuppression 4 to 8 weeks after transplantation. A subpopulation of transplanted hRPCs migrates and integrates into the mouse retina and express photoreceptor markers. These results suggest the potential of hRPC transplantation for treating retinal degenerative diseases. |
