Researchers at the National Eye Institute (NEI) are launching a clinical trial to test the safety of a novel patient-specific stem cell-based therapy to treat geographic atrophy (GA), the advanced dry form of age-related macular degeneration (AMD).
Researchers at the National Eye Institute (NEI) are launching a clinical trial to test the safety of a novel patient-specific stem cell-based therapy to treat geographic atrophy (GA), the advanced dry form of age-related macular degeneration (AMD), a leading cause of vision loss among people age 65 and older. The GA form of AMD currently has no treatment.
“The protocol, which prevented blindness in animal models, is the first clinical trial in the United States to use replacement tissues from patient-derived induced pluripotent stem cells (iPSC),” said Kapil Bharti, PhD, head of the NEI Ocular and Stem Cell Translational Research Section.
The therapy involves taking a patient’s blood cells and, in a lab, converting them into iPS cells, which have the potential to form almost any type of cell in the body. The iPS cells are programmed to become retinal pigment epithelial (RPE) cells, the type of cell that dies early in the GA stage of macular degeneration.
RPE cells nurture photoreceptors, the light-sensing cells in the retina. In GA, once RPE cells die, photoreceptors eventually also die, resulting in blindness. The therapy is an attempt to shore up the health of remaining photoreceptors by replacing dying RPE with iPSC-derived RPE.
Before they are transplanted, the iPSC-derived RPE are grown in sheets one cell thick, replicating their natural structure within the eye. This monolayer of iPSC-derived RPE is grown on a biodegradable scaffold designed to promote the integration of the cells within the retina.
Surgeons position the patch between the RPE and the photoreceptors using a surgical tool designed specifically for that purpose. (Figure 1)
1. Sharma R, Khristov V, Rising A, Jha BS, Dejene R, Hotaling N, Li Y, Stoddard J, Stankewicz C, Wan Q, Zhang C, Campos MM, Miyagishima KJ, McGaughey D, Vilasmil R, Mattapallil M, Stanzel B, Qian H, Wong W, Chase L, Charles S, McGill T, Miller S, Maminishikis A, Amaral J, Bharti K. Patient-specific clinical-grade iPS cell-derived retinal pigment epithelium patch rescues retinal degeneration in rodent and pig eyes. Jan 16, 2019 Science Translational Medicine. DOI: 10.1126/scitranslmed.aat5580