Concise Review: Update on Retinal Pigment Epithelium Transplantation for Age-Related Macular Degeneration. (12th February 2019)

• Record Type: Journal Article
• Authors: Zarbin, Marco; Sugino, Ilene; Townes-Anderson, Ellen
• Is Part Of: Stem cells translational medicine. Volume 8:Number 5(2019)
• Page Start: 466
• Page End: 477
• Publication Date: 2019-02-12
• Subjects: Autologous stem cell transplantation -- Cell transplantation -- Clinical trials -- Experimental models -- Induced pluripotent stem cells -- Embryonic stem cells -- Retina; Stem cells -- Periodicals; Regenerative medicine -- Periodicals; Periodicals; 616.0277405
• DOI: 10.1002/sctm.18-0282
• Languages: English
• ISSNs: 2157-6564

Abstract

Abstract: Retinal cell therapy can have the objectives of rescue (i.e., modulation of metabolic abnormalities primarily for sight preservation) as well as replacement (i.e., replace cells lost due to injury or disease for sight restoration as well as preservation). The first clinical trials of retinal pigment epithelium (RPE) transplantation for vision-threatening complications of age-related macular degeneration (AMD) have begun with some preliminary signs of success (e.g., improvement in vision in some patients, anatomic evidence of transplant-host integration with some evidence of host photoreceptor recovery, long-term survival of autologous induced pluripotent stem cell-derived RPE transplants without immune suppression) as well as limitations (e.g., limited RPE suspension survival in the AMD eye, limited tolerance for long-term systemic immune suppression in elderly patients, suggestion of uncontrolled cell proliferation in the vitreous cavity). RPE survival on aged and AMD Bruch's membrane can be improved with chemical treatment, which may enhance the efficacy of RPE suspension transplants in AMD patients. Retinal detachment, currently used to deliver transplanted RPE cells to the subretinal space, induces disjunction of the first synapse in the visual pathway: the photoreceptor-bipolar synapse. This synaptic change occurs even in areas of attached retina near the locus of detachment. Synaptic disjunction and photoreceptor apoptosis associated with retinal detachment can be reduced with Rho kinase inhibitors. Addition of Rho kinase inhibitors may improve retinal function and photoreceptor survival after subretinal delivery of cells either in suspension or on scaffolds. : Abstract : The first synapse in the visual pathway involves contact between rod and cone photoreceptors and their corresponding bipolar cells. Retinal detachment and other forms of injury cause synaptic disjunction with retraction of the rod presynaptic terminal into the outer nuclear layer (right red arrow) and rounding of the cone presynaptic terminal (left red arrow) with disorganization of the synaptic ribbon and loss of synaptic invaginations by bipolar and horizontal cells.