Preliminary research shows encouraging results with transplantation of fetal stem cells in patients with retinitis pigmentosa (RP) and dry AMD, according to a report in the August issue of American Journal of Ophthalmology.
Although they have different causes, both RP and AMD lead to destruction of retinal photoreceptor cells. In theory, if the damaged photoreceptors can be replaced with new cells that connect with the remaining host retina it may be possible to restore visual function.
Investigators performed implantation of fetal retinal cells together with their attached retinal pigment epithelial cells in ten patients with vision of 20/200 or less: six patients with RP and four with the dry AMD.
Follow-up testing 5 years after implantation showed visual improvements in seven of the ten patients: three of the patients with RP and all four patients with AMD. Although vision remained in the "legally blind" range for all patients, the gains in vision were significant and measurable.
"This clinical evidence shows the promise of our method to alter progressive vision loss due to incurable degenerative diseases of the retina," comments lead author Dr. Norman Radtke.
Much further research will be needed to determine the potential for retinal transplantation to improve vision in patients with these diseases. "Retinal implants that combine retina and retinal pigment epithelium demonstrated an apparent ability to integrate with host retinas and to re-establish the visual pathways interrupted by disease," adds Dr. Radtke.
WHAT IT MEANS TO YOU: Currently, no effective treatment exists for the recovery of vision loss to degenerative retinal disease. But progress is being made. A clinical trial of gene therapy in Leber congenital amaurosis has recently reported good results. Neurotech has started phase II clinical trials for ciliary neurotrophic factor for RP. Multiple centers are actively pursuing development and use of an artificial retina. The current study demonstrates promising results using fetal stem cell implants. There is reason to be optimistic that it will soon be possible to restore vision lost to these blinding diseases.
Source:http://www.ajo.com/article/S0002-9394(08)00293-6/abstract