Researchers at the University of Wisconsin–Madison in the United States have made a significant breakthrough in the treatment of numerous eye illnesses by transplanting light-sensitive eye cells generated in the lab into patients.
The retina is a small layer of tissue at the back of the eye that contains photoreceptor cells and other cells that work together to convert different colors of light into signals the brain recognizes as images.
Scientists hope to one day be able to cultivate retinal cells outside of the body and transplant them into the eye to repair damaged or diseased retinas.
In 2014, scientists were able to create a model retina using organoids (cell clusters that self-organized into 3D shapes in the lab) that closely mimicked the structure and behavior of a genuine retina. By reprogramming human skin cells into stem cells, they were able to direct their differentiation into numerous kinds of retinal cell.
The same group of researchers reported findings last year demonstrating that retinal cells generated in the lab could sense and react to varying light intensities and colors, as well as reach out to interact with nearby cells.
Axons allow cells to communicate with one another, and a synapse acts as a chemical signal box at each junction.
It’s one thing to see axons extending between cells. The group carefully separated groups of retinal cells and monitored as they reconnected to assure successful reattachment.
Next, a rabies virus was introduced, and over the course of a week, it was shown to spread across the retinal cells, demonstrating the presence of functional synapses.
Further examination indicated that the photoreceptors, which are typically classified into rods and cones, were the cell types most actively making connections. This is promising since illnesses like retinitis pigmentosa and age-related macular degeneration destroy these cells.
Retinal ganglion cells, a kind of cell, showed signs of synapse formation. Diseases like glaucoma, which cause damage to the optic nerve leading from the eye to the brain, may benefit from the replacement of these cells in the eye.
