Japanese researchers believe they've discovered an effective way to restore vision to people suffering from late-stage retinal degeneration. Although this stem cell technique hasn't been used on humans yet, the results from mice trials are very promising.
This study took place at the RIKEN Center for Developmental Biology in Kobe, Japan. Doctors involved in this study first took cells from healthy adult mice and converted them into pluripotent stem cells. These stem cells were then used to create retinal tissues and later implanted into the eyes of mice with end-stage retinal degeneration. Amazingly, 40 percent of the mice with the retina tissues implanted were able to distinguish lights again.
Researchers were extremely proud to be a part of this historic study. This particular study represents the first official time scientists were able to effectively transplant the stem cell generated retinal tissues into the eyes of mice and have them communicate with the brain and nervous system.
For those who don't know, the retina is a thin layer of tissue at the back of the eye. Both of our retina are tasked with sensing light and sending vital visual information to the brain. People with retinal degeneration gradually lose the ability to perceive light, which could lead to total blindness. The most common form of retinal degeneration is called age-related macular degeneration. There are currently around 170 million people with macular degeneration around the world.
Researchers tested the mice's ability to perceive light by using something called a shuttle avoidance test. The mice were placed in a two-chamber box that was both sound and light insulated. A wall with one small opening in the middle separated the two chambers of the box.
Once a mouse was placed in the box, researchers trained that mouse to avoid electric shocks by playing a beeping noise and turning on a light before the mouse was zapped. The only way for the mouse to avoid the shock was to move into the other chamber. After the mouse learned to avoid the shock, the beep was taken out and only the light was used as a warning.
The final results from this test showed that four out of 10 mice with transplants in both eyes were able to avoid the shock. Also, five out of 11 mice that had a retinal transplant in one eye were able to perceive the light signal.
Researchers are hopeful these retinal transplants can soon be used on humans, but they doubt the results will be as remarkably fast as those performed on the mice. In a statement to the press, Japanese scientists noted that it only takes about one month for the retina of a mouse to fully recover from transplant surgery. Since the human retina is more complex, they expect it to take around six months for the transplanted retina to start to perceive light again.
These researchers have expressed interest in conducting a human clinical trial using the same retina procedures in the future. They also hope future stem cell generated retinal tissues will be able to make even more connections within the nervous system the next time they try out this therapy.
The full trail study was published in the medical journal Stem Cell Reports under the title "iPSC-Derived Retina Transplants Improve Vision in rd1 End-Stage Retinal-Degeneration Mice."