-- Mary Elizabeth Dallas
TUESDAY, June 10, 2014 (HealthDay News) -- Using human stem
cells, researchers created eye cells capable of responding to
Specifically, the researchers created retina cells. The retina
is a layer of light-sensitive cells that line the inside of the
eye. The retina sends visual messages to the optic nerve in the
brain to create visual images, according to the U.S. National Eye
Although the cells created by the researchers haven't yet
produced a visual signal the brain can interpret into an image, the
researchers noted that this study is just a first step. They
suggested their findings could eventually lead to the development
of genetically engineered retina cell transplants that can stop or
reverse blindness in people with retinal disease.
"We have basically created a miniature human retina in a dish that not only has the architectural organization of the retina, but also has the ability to sense light," study leader M. Valeria Canto-Soler, an assistant professor of ophthalmology at the Johns Hopkins University School of Medicine, said in a university news release.
The study, published online June 10 in
Nature Communications, involved so-called human induced
pluripotent stem cells (iPS). These are adult cells reprogrammed
into a primitive state. This allowed the researchers to turn them
into early stage retinal cells that would then go on to form the
light-sensitive retinal tissue found in the back of the eye.
Retinal tissue is made up of seven major types of cells, the
researchers explained. These cells are organized into layers that
absorb and process light. These layers also transmit the visual
signals that are interpreted by the brain. The retinal cells grown
in the lab recreated this multi-layered, three-dimensional form of
the human retina.
"We knew that a 3-D cellular structure was necessary if we wanted to reproduce functional characteristics of the retina, but when we began this work, we didn't think stem cells would be able to build up a retina almost on their own. In our system, somehow the cells knew what to do," said Canto-Soler.
While these cells were grown in a petri dish, they matured in a
manner similar to what might occur in the eyes of a developing
fetus. At the equivalent of 28 weeks' gestation, the researchers
tested the mini-retinas to see if the photoreceptors were able to
transform light into visual signals. The photoreceptors grown in
the lab responded to light in the same way as human retinas.
The study's authors said their findings provide scientists the
ability to study the cause of retinal diseases on human tissue
rather than animals. They added it may allow for the testing of
drugs to treat individual patients specifically. In the future, the
researchers suggested, diseased or dead retinal tissue may be
replaced with tissue grown in a lab, which might help reverse
blindness for some people.
The U.S. National Institutes of Health provides more information
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