97th DOG Annual Meeting 1999

K257

TRANSPLANTATION OF AUTOLOGOUS IRIS PIGMENT EPITHELIUM TO THE SUBRETINAL SPACE IN RABBITS

G. Thumann, K. U. Bartz-Schmidt, H. El Bakri, U. Schraermeyer

Transplantation of autologous iris pigment epithelium (IPE) into the subretinal space has been suggested as one approach for the treatment of age related macular degeneration (AMD). Autologous rabbit iris pigment epithelium cells were transplanted to the subretinal space to define the technique of transplantation and examine the survival of the transplanted cells.

Methods: Autologous IPE cells were harvested by iridectomy and transplanted directly to the subretinal space of the fellow eye in 25 rabbits, using the pars-plana approach. Animals were sacrificed after a period of 5 months and the retinas examined morphologically by light and electron microscopy.

Results: Autologous IPE cells survived and formed a polarized monolayer above the retinal pigment epithelium (RPE) in the subretinal space, with apical microvilli adjacent to photoreceptors. Fragments of phagocytosed photoreceptor rod outer segments (ROS) were observed in phagosomes in the cytoplasm of IPE. Adjacent ROS remained healthy throughout the experimental period. No signs of a cell mediated immunologic response were observed.

Conclusions: Our results show that in rabbits autologous IPE cells transplanted to the subretinal space survive and do not adversely affect the photoreceptors. These results suggest that in humans IPE cells might provide a substitute for RPE cells as autologous transplants for the treatment of AMD.

Univ.-Augenklinik Köln, Abt. Glaskörper- und Netzhautchirurgie, Joseph-Stelzmann-Str. 9, D-50931 Köln


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