Two patients with macular degeneration regained reading vision after receiving stem cells implanted with a new technique, according to researchers.
Professor Lyndon da Cruz from Moorfields Eye Hospital NHS Foundation Trust and his colleagues engineered a patch of retinal pigment epithelium cells from human embryonic stem cells to treat the patients, both of whom had suffered sudden severe sight loss from wet age-related macular degeneration (AMD).
The technique might also be used to treat the dry form of the disease, Professor da Cruz and his colleagues wrote in a report on the Phase I trial in Nature Biotech.
“The results suggest that this new therapeutic approach is safe and provides good visual outcomes," Professor da Cruz said. “The patients who received the treatment had very severe AMD, and their improved vision will go some way towards enhancing their quality of life.”
AMD damages the retinal pigment epithelium (RPE), a layer of cells that separates blood vessels from the nerve layer and nourishes the retina.
Human embryonic stem cells hold promise as a source for replacing damaged or missing cells because of their availability, pluripotency and unlimited capacity for self-renewal. But they come with the risk of neoplastic change, uncontrolled proliferation and differentiation to inappropriate cell types.
Suspensions of retinal pigment epithelium cells derived from human embryonic stem cells have been transplanted in human subjects with dry AMD and Stargardt’s disease, but the extent of cell survival and restoration of vision remains unclear, the researchers wrote.
A recent, single-patient report described transplantation of a retinal pigment epithelium patch derived from autologous induced pluripotent stem cells on its own secreted basement membrane. The patch survived with maintenance, but no improvement, of visual acuity at 12 months.