title: iPSC-Derived Retinal Pigment Epithelium Allografts Do Not Elicit Detrimental Effects in Rats: A Follow-Up Study.
abstract: Phototransduction is accomplished in the retina by photoreceptor neurons and retinal pigment epithelium (RPE) cells. Photoreceptors rely heavily on the RPE, and death or dysfunction of RPE is characteristic of age-related macular degeneration (AMD), a very common neurodegenerative disease for which no cure exists. RPE replacement is a promising therapeutic intervention for AMD, and large numbers of RPE cells can be generated from pluripotent stem cells. However, questions persist regarding iPSC-derived RPE (iPS-RPE) viability, immunogenicity, and tumorigenesis potential. We showed previously that iPS-RPE prevent photoreceptor atrophy in dystrophic rats up until 24 weeks after implantation. In this follow-up study, we longitudinally monitored the same implanted iPS-RPE, in the same animals. We observed no gross abnormalities in the eyes, livers, spleens, brains, and blood in aging rats with iPSC-RPE grafts. iPS-RPE cells that integrated into the subretinal space outlived the photoreceptors and survived for as long as 2 1/2 years while nonintegrating RPE cells were ingested by host macrophages. Both populations could be distinguished using immunohistochemistry and electron microscopy. iPSC-RPE could be isolated from the grafts and maintained in culture; these cells also phagocytosed isolated photoreceptor outer segments. We conclude that iPS-RPE grafts remain viable and do not induce any obvious associated pathological changes.
authors.affiliation: Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA; The Lowy Medical Research Institute, La Jolla, CA 92037, USA.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Westenskow
authors.affiliation: Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
authors.forename: Felicitas
authors.initials: F
authors.lastname: Bucher
authors.affiliation: Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Bravo
authors.affiliation: Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
authors.forename: Toshihide
authors.initials: T
authors.lastname: Kurihara
authors.affiliation: Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Feitelberg
authors.affiliation: Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
authors.forename: Liliana P
authors.initials: LP
authors.lastname: Paris
authors.affiliation: Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
authors.forename: Edith
authors.initials: E
authors.lastname: Aguilar
authors.affiliation: Department of Pathology, VA San Diego Healthcare System, University of California San Diego, La Jolla, CA 92037, USA.
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Lin
authors.affiliation: Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Friedlander