Characterization of a mouse model with complete RPE loss and its use for RPE cell transplantation

Carido M, Zhu Y, Postel K, Benkner B, Cimalla P, Karl MO, Kurth T, Paquet-Durand F, Koch E, Münch TA, Tanaka EM, Ader M.

Investigative Ophthalmology & Visual Science · 7 Aug 2014 · doi: 10.1167/iovs.14-14325

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Carido et al present the sodium iodate mouse model of age-related macular degeneration. Systemic injection of sodium iodate leads to death of retinal pigment epithelium, with subsequent photoreceptor cell death. OptoDrum measurements show that the vision loss can be tracked at the behavioral level.

Abstract

Purpose: Age-related macular degeneration (AMD) is a major leading cause of visual impairment and blindness with no cure currently established. Cell replacement of RPE is discussed as a potential therapy for AMD. Previous studies were performed in animal models with severe limitations in recapitulating the disease progression. In detail, we describe the effect of systemic injection of sodium iodate in the mouse retina. We further evaluate the useful-ness of this animal model to analyze cell-specific effects following transplantation of human embryonic stem cell (hESC)-derived RPE cells. Methods: Morphologic, functional, and behavioral changes following sodium iodate injection were monitored by histology, gene expression analysis, electroretinography, and optokinetic head tracking. Human embryonic stem cell–derived RPE cells were transplanted 1 week after sodium iodate injection and experimental retinae were ana-lyzed 3 weeks later. Results: Injection of sodium iodate caused complete RPE cell loss, photoreceptor degeneration, and altered gene and protein expression in outer and inner nuclear layers. Retinal function was severely affected by day 3 and abol-ished from day 14. Following transplantation, donor hESC-derived RPE cells formed extensive monolayers that dis-played wild-type RPE cell morphology, organization, and function, including phagocytosis of host photoreceptor outer segments. Conclusions: Systemic injection of sodium iodate has considerable effects on RPE, photoreceptors, and inner nu-clear layer neurons, and provides a model to assay reconstitution and maturation of RPE cell transplants. The avail-ability of an RPE-free Bruch's membrane in this model likely allows the unprecedented formation of extensive polar-ized cell monolayers from donor hESC-derived RPE cell suspensions.