Advances and challenges in photoreceptor repair and regeneration

Abstract

<p indent="0mm">Vision relies on converting light into electrical signals and sequentially transmitting the electrical signals along a visual pathway. Photon reception and electrical signal conversion is the first step in vision, which is carried out by a specialized type of retinal neuron called the photoreceptor. Loss of photoreceptors leads to irreversible retinal degeneration and blindness, and currently, there is no cure. Gene therapy is expected to relieve some hereditary retinal degenerative diseases. The first and the only by far gene-drug LUXTURNA® was approved by the US FDA in 2017 for the treatment of Leber congenital amaurosis (LCA). However, the high cost ($850,000/person) and narrow treatment window make it unavailable for most patients with RPE65 mutations. Recent advances in the differentiation of embryonic stem cells and induced pluripotent stem cells and in transdifferentiation of endogenous Müller cells provide hope for regenerating photoreceptors and will provide new routes for treating degenerative retinal diseases. This review focuses on the ongoing development of gene and stem cell therapies, highlighting the current advances and challenges in photoreceptor repair and regeneration.