A new breakthrough in stem cell research has brought scientists closer to the creation of laboratory-grown human eyeballs.
A team of biologists led by Koji Nishida of Osaka University has discovered a new way to obtain the many individual tissues that make up the human eyeball. For this, scientists need only a small piece of human skin. With the new method, researchers can grow the retina, cornea, lens, and more.
In preliminary tests, Japanese researchers were able to grow the cornea of a rabbit, the clear coat of the eye that restored vision to blind rabbits born with incompletely developed corneas. The research results are published in the journal Nature.
“We are now about to begin the first clinical trials in humans - by performing an anterior chamber transplant to restore visual function,” Nishida writes in an article in Nature. He believes that within the next three years he will be able to test a technique to restore a diseased or injured human cornea.
The new research builds on recent advances in stem cell technology. In 2006, scientists discovered that it was possible to create complete stem cells from normal blood cells or skin with just a few DNA manipulations.
Now scientists have found that they can make induced pluripotent stem cells (iPS) form a simple proto-eye, from which a variety of eye tissues can be derived. They managed to initiate the formation of this proto-eye by growing iPS cells in a Petri dish, adding the right combination of proteins and other molecules. Essentially, these proto-eyes are four simple rings of different types of cells that are subsequently transformed into parts of the eye such as the retina or lens. In other words, this is one of the earliest and simplest phases in the formation of the biological eye.
During the experiment, scientists initiated the formation of proto-eyes from rabbit skin cells, and then pulled out some of the developing cells from the third ring of the proto-eye. Subsequently, this ring forms the cornea and lens of the eye. The collected cells were then grown separately to form a transparent film of corneal material. Nishida then implanted this film into the eyes of blind rabbits, from which skin cells were taken to obtain iPS cells. Stem cells took root and returned sight to the animals.
Particularly important in the new study, the article notes, is that by shaping proto-eyes, scientists can obtain samples of virtually every cell type needed to repair or repair damaged eyes.
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