Ex vivo gene therapy and vision.

Ex vivo gene therapy, a technique where genetic manipulation of cells is undertaken remotely and more safely since it is outside the body, is an emerging therapeutic strategy particularly well suited to targeting a specific organ rather than for treating a whole organism. The eye and visual pathways therefore make an attractive target for this approach. With blindness still so prevalent worldwide, new approaches to treatment would also be widely applicable and a significant advance in improving quality of life. Despite being a relatively new approach, ex vivo gene therapy has already achieved significant advances in the treatment of blindness in pre-clinical trials. In particular, advances are being achieved in corneal disease, glaucoma, retinal degeneration, stroke and multiple sclerosis through genetic re-programming of cells to replace degenerate cells and through more refined neuroprotection, modulation of inflammation and replacement of deficient protein. In this review we discuss the latest developments in ex vivo gene therapy relevant to the visual pathways and highlight the challenges that need to be overcome for progress into clinical trials.