- In a major step forward for regenerative medicine, Japanese researchers succeeded for the first time to convert stem cells from mammalian embryonic eye, according to a study released Wednesday.
The findings, published in the journal Nature, opened the way for new treatments for eye diseases, and even raise the possibility that someday they can restore sight with transplanted retinas, generated from own stem cells from a patient, according to other experts.
In some experiments with laboratory mice, researchers led by Yoshiki Sasai, RIKEN Center for Biology in Kobe, Japan, began working with pluripotent stem cells, the starting point almost any specialized cell in an organism.
So far, it was believed that stem cells were only used to replace tissue, eg muscle, liver or heart, composed of a single cell type.
also thought that the generation of a more complex set of cells or organs, it was only possible through chemical interactions with other tissues during pregnancy.
However, Sasai and colleagues, using new laboratory techniques, have transformed embryonic stem cells of a mouse in a drink called optical three-dimensional structures that give rise to the retina of an eye.
Surprisingly, cells transformed by themselves, without forcing them to take any particular form, the researchers said.
In the experiment, stem cells, in principle, a mass without any pattern, became a form provided with two walls, for inner and outer layers of the retina during the development of an embryo.
"What we've done is solve a problem for almost a century embryology, showing that the founding fathers retinal have the inherent capacity to generate the complex structure of the optic cup, Sasai said in a statement.
"We are on track to generate not only different types of cells but organized tissues" that can be used in regenerative medicine, according Sasai.
The scientist stressed that the finding is especially relevant to an eye disease of genetic origin of retinitis pigmentosa, which causes blindness.
The disease attacks the eye damaging the retina, the layer of tissue behind the eye that converts light images into nerve signals and sends to the brain.
patients suffering from retinitis pigmentosa suffer a gradual loss of vision because photoreceptor cells, composed of rods and cones degenerate and die.
"As a step forward in efforts cell replacement therapy or organ, is a very important job," said Richard Lang, a specialist at Cincinnati Children's Hospital, after seeing the study.
"A striking proof of this is genuine is retinas, in the stage of growth, the synthetic optical glasses undergo cellular differentiation, giving result in "all major types of retinal cells, including photoreceptors," wrote Robin Ali and Jane Snowden of University College London, in a commentary published in Nature.
Lang said, however, that in order to generate tissues for the human eye is far, but noted that other teams of scientists to make significant advances with other types of tissues. Olivier
Goureau, researcher at the Eye Institute in Paris, agrees that the study breaks new ground, noting however that the eyes of mice and humans differ.
"Training the eyes are the same, but most of the rodents, for example, used the cones in the same way that human beings, "he said by telephone.
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