National Eye Institute (NEI) researchers have developed an in vitro model for studying pigmentation defects in human retinal pigment epithelium (RPE). The ‘disease-in-a-dish’ system is the first instance of using patient-derived stem cells as a model for studying eye conditions related to oculocutaneous albinism (OCA). Individuals with OCA lack pigmented RPE and have an underdeveloped fovea, an area within the retina that is crucial for central vision.
“This ‘disease-in-a-dish’ system will help us understand how the absence of pigment in albinism leads to abnormal development of the retina, optic nerve fibers, and other eye structures crucial for central vision,” said Aman George, Ph.D., a staff scientist in the NEI Ophthalmic Genetics and Visual Function Branch, and the lead author of the report.
To make the model, researchers reprogrammed skin cells from individuals without OCA and people with the two most common types of OCA (OCA1A and OCA2) into pluripotent stem cells (iPSCs). The iPSCs were then differentiated to RPE cells. The RPE cells from OCA patients were identical to RPE cells from unaffected individuals but displayed significantly reduced pigmentation.
The researchers will use the model to study how lack of pigmentation affects RPE physiology and function. In theory, if fovea development is dependent on RPE pigmentation, and pigmentation can be somehow improved, vision defects associated with abnormal fovea development could be at least partially resolved, according to Brooks.
“Treating albinism at a very young age, perhaps even prenatally, when the eye’s structures are forming, would have the greatest chance of rescuing vision,” said Brooks. “In adults, benefits might be limited to improvements in photosensitivity, for example, but children may see more dramatic effects.”
The team is now exploring how to use their model for high-throughput screening of potential OCA therapies.
Full news release: www.nei.nih.gov/about/news-and-events/news/nih-researchers-develop-first-stem-cell-model-albinism-study-related-eye-conditions
Source: National Eye Institute