Embryonic stem cells as a treatment for macular degeneration.

INTRODUCTION: Retinal degenerations are typically characterized by loss of highly differentiated cell types within the neurosensory retina, such as photoreceptors, or retinal pigment epithelium (RPE). RPE loss is the final common pathway in a number of degenerations including the leading cause of new blindness in the developed world: age-related macular degeneration (AMD). AREAS COVERED: This paper presents the pathophysiologic case for RPE transplantation with stem cell (SC)-derived tissue, a review of the preclinical data substantiating the hypothesis and the initial clinical trials safety data from early human trials. EXPERT OPINION: Targeting the RPE for transplantation with SC-derived tissue presents a reasonable therapeutic opportunity in a variety of important, otherwise untreatable, blinding conditions. Success of cellular replacement strategies is contingent on finding a viable source of replacement cells, establishing a safe technique for delivery and survival of transplanted cells within the host, restoration of normal retinal architecture and stabilization or improvement of vision.