LONDON (TIP): British scientists have grown the lightsensitive cells of the eye in a lab with the help of an artificial retina. This may pave way for restoring eyesight of blind people using stem-cell transplants , a new study has found. University College London scientists grew a synthetic retina in a dish and then successfully implanted it in a blind mice, carrying out the first successful transplant of light-sensitive photoreceptor cells (extracted from the synthetic retina).
When transplanted into night-blind mice these cells appeared to develop normally, integrating into the existing retina and forming the nerve connections needed to transmit visual information to the brain. Scientists may have been unable to show any improvement in the vision of the blind mice, however , they are confident that this will soon be possible in further experiments . Researchers said the development should enable them to move to the first clinical trials on patients within five years.
The new 3D technique mimics normal development, which means doctors are able to pick out and purify the cells at precisely the right stage to ensure successful transplantation. The team grew retinal precursor cells using the new 3D culture method and compared them closely with cells developed normally, looking for different markers at different stages of development. They also carried out tests to look at the genes being expressed by the two types of cells to make sure they were biologically equivalent.
They then transplanted around 200,000 of the labgrown cells by injecting them into the retina of night blind mice. Three weeks after transplantation the cells had moved and integrated into the recipient mouse retina and were beginning to look like normal mature rod cells. These cells were still present six weeks after transplantation.
The researchers also saw nerve connections (synapses), suggesting that the transplanted cells were able to connect with the existing retinal circuitry. Doctors said, “Now that we have proved the proof-of-concept , the road is clear to the first set of trials on humans just to see whether it’ll work.”