Three months after transplantation, immunofluorescence studies confirmed the survival of the chemically induced photoreceptor-like cells (green), integrated in the retinal layers. Credit: Dr Sai Chavala, Circ Therapeutics

A National Eye Institute (NEI) study has successfully reprogrammed skin cells into light-sensing photoreceptors. 

The study, published by Nature, demonstrated how lab-made photoreceptor rods enabled blind mice to detect light after the cells were transplanted in their eyes. Until now, researchers have replaced dying photoreceptors in animal models using stem cells from skin or blood, programmed to become photoreceptors. But in this study, scientists successfully skipped the lengthy stem-cell intermediary step and directly reprogrammed skin cells, which were then ready for retina transplantation in just 10 days.  

“Our technique goes directly from skin cell to photoreceptor without the need for stem cells in between,” said lead investigator Dr Sai Chavala, president of Circ Therapeutics and the Center for Retina Innovation in Dallas, Texas.  

Three months after transplantation, immunofluorescence studies confirmed the survival of the lab-made photoreceptors, as well as their synaptic connections to neurons in the inner retina of the mouse eye. Further research is needed to optimise the protocol to increase the number of functional transplanted photoreceptors, said researchers.  

“If efficiency of this direct conversion can be improved, this may significantly reduce the time it takes to develop a potential cell therapy product or disease model,” said senior investigator Kapil Bhart, NEI’s head of ocular and stem cell translational research.  

A clinical trial to test the therapy in humans for degenerative retinal diseases, such as retinitis pigmentosa, is in the pipeline, said Dr Chavala.