Mouse embryonic stem cells have been successfully used by scientists to replace diseased retinal cells and restore sight in a mouse model of retinitis pigmentosa.
According to the research team led by Columbia University Medical Center, this strategy could potentially become a new treatment for retinitis pigmentosa, a leading cause of blindness that affects approximately one in 3,000 to 4,000 people, or 1.5 million people worldwide.
Specialized retinal cells called the retinal pigment epithelium maintain vision. Retinitis pigmentosa results from the death of retinal cells on the periphery of the retina, leading to "tunnel vision," where the field of vision is narrowed considerably and everything outside the "tunnel" appears blurred or wavy.
"This research is promising because we successfully turned stem cells into retinal cells, and these retinal cells restored vision in a mouse model of retinitis pigmentosa," said Stephen Tsang, assistant professor of ophthalmology, pathology and cell biology, Columbia University Medical Center, and lead author of the paper.
"The transplanted cells not only looked like retinal cells, but they functioned like them, too," he added.
In Tsang's study, sight was restored in one-fourth of the mice that received the stem cells.
However, complications of benign tumours and retinal detachments were seen in some of the mice, so Tsang and colleagues will optimize techniques to decrease the incidence of these complications in human embryonic stem cells before testing in human patients can begin.
"Once the complication issues are addressed, we believe this technique could become a new therapeutic approach for not only retinitis pigmentosa, but age-related macular degeneration, Stargardt disease, and other forms of retinal disease that also feature loss of retinal cells," said Tsang.
The study appears online ahead of print in the journal Transplantation.