Stem Cell Research in AMD

Baltimore Washington Eye Center, Maryland

Thursday, March 22, 2012

Stem Cell Research in AMD

Stem cells have the ability to differentiate into any type of cell found in human tissue. They have long been believed to hold the key to the treatment and prevention of a host of devastating diseases. Age related macular degeneration along with glaucoma and cataracts, is one of the leading causes of blindness worldwide. Loss of vision from cataracts is reversible with cataract surgery. Glaucoma, when caught early, can be managed to prevent severe visual loss. For the majority of patients with macular degeneration, there is no effective management of the disease.

The retina can be thought of, in simplified terms, as being made up of three basic layers sandwiched together. A layer of seeing cells (rods and cones), a layer of blood vessels (the choroid) and sandwiched between them a layer of pigmented cells (retinal pigment epithelium or RPE). The function of the retinal pigment epithelium is the metabolic support of the other two layers. In macular degeneration, it is the RPE that fails. Once the RPE stops functioning well, either of the other two layers may malfunction. When trouble occurs in the choroid, it manifests as abnormal growth of blood vessels that leak and bleed, resulting in retinal scarring and severe visual loss (Wet AMD). Happily, with recent developments in injectable medications, treatments exist for this devastating form of the disease. In over eighty percent of patients with this disease, the seeing cells of the retina atrophy over time (Dry AMD) causing a slow insidious loss of vision that currently we have no ability to treat or prevent.

In July of last year, as reported in the Los Angeles Times, stem cells that had been differentiated into retinal pigment epithelial cells, were injected into the retinas of patients suffering from dry AMD as well as Stargardt’s disease, a genetic disease that causes progressive retinal degeneration and severe vision loss in young people. The study was primarily done to determine the safety of such treatments, as the patients in the study all had such advanced disease that no improvement of vision could reasonably be expected. A preliminary report published in the journal Lancet in January 2012, stated that there were no adverse effects of treatment and no rejection of the transplanted cells. This evidence paves the way for future studies in patients with less advanced disease. And the hope exists that halting of the disease or recovery of vision, may be on the horizon.

Shari E. Strier, O.D. with the Baltimore Washington Eye Center