Lab- Grown Retina Transplanted Successfully

Scientists have now successfully restored retinal cells in blind mice by transplanting light-sensitive photoreceptor cells in the retina. The cells were obtained from embryonic stem cells and were grown in a lab. The new therapy could offer an endless supply of retina cells that could be used to treat blindness.

The research team from University College London (UCL) found that the transplanted stem cells integrated with the existing retina cells and formed nerve connections that are required to send visual information to the brain.

Loss of photoreceptors in the retina is the leading cause of blindness in diseases such as age-related macular degeneration, retinitis pigmentosa and diabetes-related blindness.

About 40 to 45 percent of all Americans diagnosed with diabetes are at some stage of diabetic retinopathy, according to National Eye Institute.

There are two kinds of light-sensitive cells in the retina- the rods and the cones. The rods are especially important as they are extremely sensitive to even low intensity of light.

In the study, researchers took embryo cells from mice and cultured them in a lab dish where they grew into immature photoreceptors. Around 200,000 of these cells were then injected into the mice retina. In about three weeks, the blind mice retina began looking like a retina of a normal mouse. The cells were even present after six weeks and had made all the nerve connections required to send information to the brain. Scientists then tested the mice' ability to see, via various exams, reports Medical Xpress.

The technique that the team used to grow the specific kind of stem cells was developed in Japan.

"Over recent years scientists have become pretty good at working with stem cells and coaxing them to develop into different types of adult cells and tissues. But until recently the complex structure of the retina has proved difficult to reproduce in the lab. This is probably because the type of cell culture we were using was not able to recreate the developmental process that would happen in a normal embryo," Professor Robin Ali, UCL Institute of Ophthalmology and Moorfields Eye Hospital, lead author of the study said in a news release.

"The new 3D technique more closely mimics normal development, which means we are able to pick out and purify the cells at precisely the right stage to ensure successful transplantation. The next step will be to refine this technique using human cells to enable us to start clinical trials," Ali added.

The study is published in the journal Nature Biotechnology.