Cell Replacement Therapy for Retinal and Optic Nerve Diseases: Cell Sources, Clinical Trials and Challenges

The aim of this review was to provide an update on the potential cell therapies restore or replace damaged and/or lost cells in retinal degenerative and optic nerve diseases, describing available sources challenges involved such treatments when these techniques are applied real clinical practice. Sources include human fetal stem cells, allogenic cadaveric adult hippocampal neural CNS ciliary pigmented epithelial limbal progenitor (RPCs), pluripotent (PSCs) (including both embryonic (ESCs) induced (iPSCs)) mesenchymal (MSCs). Of these, RPCs, PSCs MSCs have already entered early-stage trials since they can all differentiate into RPE, photoreceptors ganglion demonstrated safety, while showing some indicators efficacy. Stem/progenitor for diseases still drawbacks, as inhibition proliferation differentiation vitro (with exception RPE) limited long-term survival functioning grafts vivo. Some other issues remain be solved concerning translation cell-based therapy, including (1) ability enrich specific subtypes; (2) survival; (3) delivery, which may need incorporate a scaffold induce correct polarization, increases size retinotomy surgery and, therefore, chance severe complications; (4) localized detachment perform subretinal placement transplanted cell; (5) evaluation risk tumor formation caused by undifferentiated prolific cells. Despite challenges, stem/progenitor represent most promising strategy disease treatment near future, therapeutics assisted gene techniques, neuroprotective compounds artificial devices fulfil needs.