A retina that could respond to light was created in a dish using stem cells. This is the first report of a successful attempt to create a functional, light-sensitive retina initiated from stem cells in the laboratory. The potential benefit from this research is to create retinas in the lab that can then be transplanted into the eyes of people who are blind.
Many types of blindness are due to the loss of retinal cells, such as the photoreceptors (rods and cones), and these types of cells never grow back after being damaged. Millions of people could have vision restored with the availability of retinal transplants. Age-related macular degeneration, or AMD, is one of the eye diseases that causes loss of retinal cells and results in blindness. This disease affects a large percentage of the elderly population. A retinal transplant derived from stem cells would be a way to cure AMD and return sight to the affected individual.
Another benefit of having retinas grown in dishes in the lab is they can be used as models for the study of various retinal diseases. The retina which was developed in the dish in this study also recapitulated the natural process of development. This means scientists can study the process of retinal development with the stem cell produced model.
A team of scientists from Johns Hopkins University carried out the research to create a three-dimensional retina with light-sensitive photoreceptors using stem cells. Dr. M. Valeria Canto-Soler, an assistant professor of ophthalmology, was the lead scientist in this effort and a report of this research was recently published in Nature Communications.
The stem cells which were used in this experiment were induced pluripotent stem cells, or iPSCs, which had the same ability to differentiate into different types of cells as embryonic cells. The stems cells used in the study originated from skin cells which were “tricked” into reverting back into behaving like an embryonic cell.
One of the remaining problems which will need to be solved is how to get the retina to hook up to the brain in such a way to create proper visual perceptions. If retinal transplants are to be successful in producing sight, the retinal cells, called ganglion cells, must have axons that form an optic nerve to carry the information to the brain. The brain, in turn, must “read” the information from the retina correctly.
The successful creation of an organ of the body, and especially a part of the nervous system, can provide lessons for the creation of other parts of the body. A liver, a kidney, and possibly even a heart could be the next organs which can be produced in the laboratory. A benefit from using stem cells to make organs for transplantation would be that the stem cells could come from the recipient’s own body, making immune response rejection less likely.
Creating a retina with stem cells in a dish is something which was only a scenario in science fiction in the recent past. The report of successfully inducing a dish of stem cells to create a functioning retina is a definite signpost of the value of stem cell research.
By Margaret Lutze