Title:Stem Cell-based Treatment Strategies for Degenerative Diseases of the
Retina
Volume: 17
Issue: 3
Author(s): Deepthi S. Rajendran Nair and Biju B. Thomas*
Affiliation:
- Department of Ophthalmology, Roski Eye Institute, Keck School of Medicine, University of Southern California, Los
Angeles, California CA, USA
- USC Ginsburg Institute for Biomedical Therapeutics, University of Southern California,
Los Angeles, California CA, USA
Keywords:
Retinal degenerative disease, retinitis pigmentosa (RP), age-related macular degeneration (AMD), stem cell therapy, retinal progenitor cells, ESC-RPE, iPSC-RPE.
Abstract:
Background: The main cause of progressive vision impairment in retinal degenerative diseases is the dysfunction of photoreceptors and the underlying retinal pigment epithelial cells. The inadequate regenerative capacity of the neural retina and lack of established therapeutic options demand the development of clinical-grade protocols to halt the degenerative process in the eye or replace the damaged cells by using stem cell-derived products. Recently, stem cell-based regenerative therapies have been at the forefront of clinical investigations for retinal dystrophies.
Objective: This article will review different stem cell-based therapies currently employed for retinal degenerative diseases, recent clinical trials, and major challenges in the translation of these therapies from bench to bedside.
Methodology: A systematic literature review was conducted to identify potentially relevant articles
published in MEDLINE/PubMed, Embase, ClinicalTrials.gov, Drugs@FDA, European Medicines
Agency, and World Health Organization International Clinical Trials Registry Platform.
Results: Transplantation of healthy cells to replace damaged cells in the outer retina is a clinically
relevant concept because the inner retina that communicates with the visual areas of the brain remains
functional even after the photoreceptors are completely lost. Various methods have been
established for the differentiation of pluripotent stem cells into different retinal cell types that can
be used for therapies. Factors released from transplanted somatic stem cells showed trophic support
and photoreceptor rescue during the early stages of the disease. Several preclinical and phase I/II
clinical studies using terminally differentiated photoreceptor/retinal pigment epithelial cells derived
from pluripotent stem cells have shown proof of concept for visual restoration in Age-related
Macular Degeneration (AMD), Stargardt disease, and Retinitis Pigmentosa (RP).
Conclusion: Cell replacement therapy has great potential for vision restoration. The results obtained
from the initial clinical trials are encouraging and indicate its therapeutic benefits. The current
status of the therapies suggests that there is a long way to go before these results can be applied
to routine clinical practice. Input from the ongoing multicentre clinical trials will give a more
refined idea for the future design of clinical-grade protocols to transplant GMP level HLA matched
cells.
