A study published in Nature reports the ability to restore a degree of vision to blind mice, using rod photoreceptors generated directly from skin cells.
The loss of photoreceptors due to age-related macular degeneration and other diseases is a leading cause of blindness in older people. The ability to reverse this loss would be a huge advancement in the field of rejuvenation therapy. Previous attempts have been focused on generating pluripotent stem cells, which could then be reprogrammed to become photoreceptors and implanted into the back of the eye. However, the process of reprogramming stem cells takes time, with up to six months required before tissue is ready for implantation.
In this study, researchers were able to use a cocktail of chemicals to skip the pluripotent stem cell phase entirely, reprogramming skin cells directly into rod photoreceptors that were ready for implantation after just 10 days.
This is the first study to show that direct, chemical reprogramming can produce retinal-like cells, which gives us a new and faster strategy for developing therapies for age-related macular degeneration and other retinal disorders caused by the loss of photoreceptors.Anand Swaroop, Ph.D., senior investigator in the NEI Neurobiology, Neurodegeneration, and Repair Laboratory
Researchers restore sight in mice by turning skin cells into light-sensing eye cells. (1586). Retrieved 17 April 2020, from https://www.eurekalert.org/pub_releases/2020-04/nei-rrs041320.php
When these cells were implanted into a mouse model of retinal degeneration, the pupillary reflex was restored in 6 out of 14 mice (compared to none of the untreated mice) after 3-4 weeks, indicating that they had recovered a degree of visual function. The treated mice also sought out dark spaces, a behaviour that would require some ability to sense light and dark.
A clinical trial of this approach in humans with retinal degeneration diseases is being planned, but this study may also have implications beyond restoring vision. The researchers were able to understand the cellular mechanism by which skin cells were directly transformed, meaning that scientists may be able to apply this technique to other cell types and therapies.
Pharmacologic fibroblast reprogramming into photoreceptors restores vision: https://doi.org/10.1038/s41586-020-2201-4
Researchers restore sight in mice by turning skin cells into light-sensing eye cells: https://www.eurekalert.org/pub_releases/2020-04/nei-rrs041320.php