Purchase this article with an account.
David F. Friedlander, Peter D. Westenskow, Toshihide Kurihara, Junhua Wang, Alison L. Dorsey, Stephen Bravo, Gary Siuzdak, Martin Friedlander; Ips-derived Rpe Demonstrate Both Trophic Rescue And Functional Phagocytosis Of Photoreceptor Outer Segments Following Implantation In Diseased Rat Eyes. Invest. Ophthalmol. Vis. Sci. 2012;53(14):5849.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Transplantation of stem cell-derived RPE cells has been shown by several groups to mediate photoreceptor rescue in rodent disease models of retinal degeneration. However, whether these cells provide trophic support or actually function to phagocytose photoreceptor outer segment (POS) remains to be determined. To assess such functional capacity, we implanted iPS-RPE into rodent models of RPE-mediated retinal degeneration (Royal College of Surgeons rats), whose RPE are unable to phagocytose shed POS and later assessed implanted cells for evidence of RPE phagocytosis.
RPE cells were derived from iPS cells reprogrammed with OCT4 and small molecules using directed differentiation techniques. After expansion and characterization they were implanted subretinally into RCS rats. Implanted RPE cells were examined for autofluorescence using confocal microscopy and for internalized phagocytosed debris using electron microscopy. High resolution LC-MS was used to detect and quantify end-products of phagocytosis and visual cycling. Focal ERG (fERG) was utilized to determine if implanted RPE cells mediated functional rescue of host photoreceptor cells.
In uninjected RCS rat eyes, a thick and diffuse band of autofluorescence was detected in the subretinal space corresponding with a debris layer. However, in eyes injected with iPS-RPE, autofluorescence was detected in the implanted RPE cells themselves, suggesting active phagocytosis. Material strongly resembling photoreceptor outer segments was also observed in implanted iPS-RPE at stages as late as 15 months after implantation. Furthermore, LC-MS data show that less A2E and higher levels of retinal accumulated in eyes implanted with iPS-RPE, demonstrating functionality of the implanted cells. Finally, fERG assays demonstrate significant functional improvement of host photoreceptors.
iPS-RPE function in vivo to mediate anatomical and functional rescue of photoreceptors by both providing trophic support and phagocytosing debris, thereby maintaining visual cycling.
This PDF is available to Subscribers Only