Nearly 11 million Americans suffer from age-related macular degeneration (AMD), the leading cause of vision loss in people 65 and older. Currently, no cure exists.
But now the federally run National Eye Institute has announced plans to begin human trials of a stem cell therapy to treat the disease, pending FDA approval. The treatment technique avoids the use of embryonic stem cells, which require the destruction of human embryos, and instead uses alternative lab-produced cells called induced pluripotent stem cells (iPSCs). If the human trials gain approval, it will be the first time researchers have used iPSCs to treat a human disease, said National Eye Institute researcher Kapil Bharti in a statement. And since iPSCs are made with a patient’s own cells, they face a minimal chance of rejection once implanted.
In the advanced stages of AMD, retinal pigment epithelial cells (RPEs) begin to die. Light-sensing cells in the retina, or photoreceptor cells, depend on the RPEs to supply them with nutrition and oxygen. When RPEs die, so do the retinal cells, causing blindness.
In animal studies described in the Jan. 16 issue of Science Translational Medicine, the researchers took iPSCs derived from rat and pig blood cells and programmed them to become RPEs. They then grew these cells into small, thin sheets and inserted them into the animals’ eyes between their RPEs and photoreceptor cells. The lab-made RPEs integrated with the animals’ retinas within 10 weeks and kept the remaining photoreceptor cells alive, stopping progression of the disease.
Any stem cell therapy involves the potential risk that the cells will form tumors, but when the researchers analyzed their lab-created cells, they found no mutations that would lead to tumor growth.