Gene therapy in optic nerve disease.

PURPOSE OF REVIEW Highlight some of the recent advances in gene therapy and gene modification for optic nerve disease to promote axon regeneration, neuroprotection, and increased visual functioning. RECENT FINDINGS Visual loss secondary to optic nerve damage occurs in numerous ophthalmologic and neurologic conditions. Damaged retinal ganglion cells (RGCs) do not regenerate once they undergo apoptosis after injury. Gene therapy has been studied to replace gene mutations in disorders affecting the optic nerve as well as to alter genes responsible for suppressing or activating pathways of optic nerve growth and regeneration. Recent clinical trials for Leber's Hereditary Optic Neuropathy have demonstrated safety and feasibility as potential future treatment. Animal studies utilizing gene therapy for optic nerve regeneration have shown various degrees of RGC axon regrowth and target reinnervation. Some studies have also successfully demonstrated a state of neuroprotection in RGCs allowing them to survive in greater numbers following injury. SUMMARY Additional studies will have to evaluate long-term efficacy and safety of these potential treatments, as well as the consequences of manipulating tumor suppressor genes and oncogenes.