The research will be published in the journal Science as the basis for the development of therapies for eye diseases such as macular degeneration and color blindness. At the same time, support the "organoids " artificial laboratory as a model of the early study of human development at the cellular level.
Artificial Retina and color blindness
"we carefully look like original eyes that developed normally, " said Robert Johnston, a developmental biologist at Johns Hopkins, "in the system model which you can learn without human manipulation directly. "
Johnston laboratory explores how the fate of the cells is determined--or what happens in the womb to change the developing cells to become specific cell types, an aspect of human biology is largely unknown.
Here, he and his team focus on cells that lets people see the blue, red, and green-three photoreceptors in the human eye.
While most of the research done on the vision of mice and fish, none of these species have a vision and dynamic colours such as belonging to a man. So tim Johnston created the human eye they need-with stem cells.
"Vision color trikromatik describes (difference) us from most other mammals, " said lead study author Kiara Eldred, a Johns Hopkins graduate student. "Research we're really trying to figure out what path it takes these cells to give us vision special color. "
For months, when cells grow in the laboratory and into the retina evolves, the team found the blue detector cells appear first, followed by the detector cells of red and green. In both cases, they found the key to the molecular switch is the ebb and flow of the flow of the thyroid hormone. That is important, the level of this hormone is not controlled by the thyroid gland, which of course there is no research in the medium, but entirely by the eye itself.
Understand how the amount of thyroid hormone determines whether cells become blue or red and green, the team was able to manipulate the result: creating retina which will see only blue, and can only see green and red.
The finding that thyroid hormone is essential for making conical merah-hijau gives an insight into why premature babies, who have lower levels of thyroid hormones because they lack a supply of the mother, have a more impaired incident height.
"If we can answer what leads cells to change, we will be closer to be able to restore vision color for people with impaired photoreceptors, " said Eldred, "this is a question that is very beautiful, nice visually as well as intellectual-what allowed we see color? n "
This finding is the first step for the laboratory. In the future they would like to use an organoid to learn much more about color vision and the mechanisms involved in the creation of the area of the retina, such as degeneration. Because macular degeneration is one of the leading causes of blindness in humans. Understand how to cultivate new degeneration can lead to clinical care.
"What's interesting about this is the job we assign human organoid system as a model for studying the mechanism of human development. Organoid takes nine months to develop. Just like human babies. So that in fact we learned is the mechanism of fetal development. "
Color blindness and Strong Medicine
In another study, researchers Mount Sinai has shown that color blindness caused by retinal damage at the cellular level, can be generated from high doses of sildenafil citrate-popular erectile dysfunction drugs sold under the brand name Viagra. The results showed that use of excessive medicines can cause long-term vision problems, including the possibility of permanent damage.
"People often live with the philosophy that if a little is good, then the resulting more and more also the better. This study shows just how dangerous a large dose of a drug that is commonly used, "said Chief Researcher Richard Rosen, MD, Director of the retinal Services at the New York Eye and Ear Infirmary of Mount Sinai (NYEE), " people who rely on color vision to their livelihoods need to be aware there might be long-term impact of consuming too much of this drug. "