Stem cell therapies have the unique ability to treat patients who have a wide range of diseases and conditions. In previous articles we discussed how scientists have been studying the effects of stem cell therapy on osteoarthritis, obsessive-compulsive disorder and multiple sclerosis.
Now, researchers are trying to figure out whether iPSC-derived retinal tissue can help patients who have outer retinal degeneration see again. They recently used the procedure on mice, and it worked.
"End-stage retinal-degeneration is the most advanced stage of age-related macular degeneration."
What is end-stage retinal-degeneration
End-stage retinal degeneration is the most advanced stage of age-related macular degeneration, an irreversible eye condition that causes people typically aged 50 and older to lose their vision.
This type of condition damages the macula – a small area near the back of the retina that contains millions of cells used to sense light and see, according to the National Eye Institute. When age, smoking or other factors (race, genetics) damages the macula, a person's vision become dark, blurry or distorted, NEI noted. Those with late-staged AMD or end-stage retinal degeneration are likely to experience complete, permanent vision loss.
The study's procedures and conclusion
The new study conducted by Michiko Mandai, senior study author of the RIKEN Center for Developmental Biology, hoped to find that cell replacement would cure this eye condition.
Mandai said the team of researchers successfully restored the vision of a group of mice with end-stage retinal degeneration after inserting iPSC stem cells into them. Researchers found that about half of the mice were able to see after the procedure.
"We showed the establishment of host-graft synapses in a direct and confirmative way," Mandai said according to Cell Press. "No one has really shown transplanted stem cell-derived retinal cells responding to light in a straightforward approach as presented in this study, and we collected data to support that the signal is transmitted to host cells that send signals to the brain."
To conduct the study, researchers converted iPSCs into retinal tissue and then inserted these cells into affected mice. From there the iPSCs formed photoreceptors, key components of the eye, which allowed it to connect with other cells in the retina.
To test whether the mice's vision was restored, they placed the animals into a box with different chambers. Two chambers had floors that transmitted an electrical shock when touched. Scientists used a warning light to help the mice avoid these floors and move to the safer chamber. Most of the mice – those that could see the light – complied.
The next step is to figure out whether researchers can use human iPSC-derived retinal tissue in people that have end-stage retinal degeneration to help them see again. To do so, researchers are testing human iPSC-derived retinal tissue in animals. Takahashi said this type of stem cell therapy is new, and explained that it's not practical at the moment to assume that it can restore complete vision. Right now it can help animals see light, but the goal is likely to progress the therapy so animals and humans can see objects.