Retinal pigment epithelium transplantation: concepts, challenges, and future prospects

Abstract

The retinal pigment epithelium (RPE) is a single layer of cells that supports the light-sensitive photoreceptor cells that are essential for retinal function. Age-related macular degeneration (AMD) is a leading cause of visual impairment, and the primary pathogenic mechanism is thought to arise in the RPE layer. RPE cell structure and function are well understood, the cells are readily sustainable in laboratory culture and, unlike other cell types within the retina, RPE cells do not require synaptic connections to perform their role. These factors, together with the relative ease of outer retinal imaging, make RPE cells an attractive target for cell transplantation compared with other cell types in the retina or central nervous system. Seminal experiments in rats with an inherited RPE dystrophy have demonstrated that RPE transplantation can prevent photoreceptor loss and maintain visual function. This review provides an update on the progress made so far on RPE transplantation in human eyes, outlines potential sources of donor cells, and describes the technical and surgical challenges faced by the transplanting surgeon. Recent advances in the understanding of pluripotent stem cells, combined with novel surgical instrumentation, hold considerable promise, and support the concept of RPE transplantation as a regenerative strategy in AMD.

Irreversible Photoreceptors and RPE Cells Damage by Intravenous Sodium Iodate in Mice Is Related to Macrophage Accumulation

“…3,4 Thus, a dysfunction of the RPE can lead to retinal diseases such as agerelated macular degeneration (AMD) and photoreceptor degeneration. 5,6 AMD is a degenerative retinal-choroidal disease and the leading cause of blindness in the elderly in developed countries. 7 Exudative AMD is characterized by choroidal neovascularizations, and nonexudative AMD is characterized by geographic atrophy of the RPE.…”

Zelltransplantation zur Behandlung der altersabhängigen Makuladegeneration

“…Intra-und postoperative Komplikationen zehren die mögliche Sehverbesserung auf. Trotzdem hält das wissenschaftliche Interesse an den Transplantationsverfahren an [8]. Bis heute gibt es für 90 % der AMD-Patienten, diejenigen mit der trockenen Verlaufsform, keine Behandlungsoption.…”

Effects of low-level laser irradiation on proliferation and functional protein expression in human RPE cells

“…Numerous studies have showed encouraging results by transplanting RPE suspensions or RPE sheets into the subretinal space of animal models [4][5][6][7]. However, AMD patients who received RPE transplantation did not achieve significant visual improvements in FDAapproved clinical trials [8,9].…”