Embryonic stem cells restore vision
Scientists from the University of Montreal have created a new method that can be used to treat age–related macular degeneration - a serious disease in which a person loses his eyesight, Infox reports.
To what extent this is a new method is not completely clear: the results of a similar work, and not on a mouse model (which is not mentioned in the retelling), but in a pilot clinical study on four volunteers, were recently published by Korean VM researchers.
The authors suggest using human embryonic cells to grow retinal cells from them that can perceive light, and then implant them into the eye.
"With the help of our method, it is possible to achieve that approximately 80% of all embryonic cells turn into cones (photoreceptor cells, ed.). Within 45 days, these cones self-organize into retinal tissue with a thickness of 150 microns. No one has been able to get such a result before," says the lead author of the study, Professor Gilbert Berner (in a press release from the University of Montreal Restoring vision with stem cells – VM).
Recall that rods and cones are special retinal cells that convert light first into chemical reactions, and then into an electrical nerve impulse. Their physiological properties have long been known: rods perceive the world in black and white, and cones are responsible for color vision, but scientists still do not know all the genes that determine the development of those and other photoreceptors.
Attempts to grow sticks and cones from stem cells have been going on for a long time and successfully. Recently, an important step has been taken in this direction – the safety committee of the Ministry of Health of Japan for the first time approved the use of induced pluripotent stem cells obtained from the skin of the patient himself for the treatment of age-related macular degeneration. The first operation to transplant such cells to a 70-year-old patient successfully took place in Japan in 2014. Then, the skin cells of the patient herself were used to obtain induced pluripotent stem cells. Already during implantation, induced pluripotent stem cells turned into rods and cones.
In their current experiment, Canadian scientists decided to go the other way and used human embryonic stem cells to grow rods and cones.
Since 1997, Professor Berner has been searching for genes that are responsible for the formation of these receptors during intrauterine development. In 2001, he managed to discover the COCO molecule, which is formed at the moment when photoreceptors are formed. But only recently scientists have managed to understand how this molecule works. Then, with the help of certain signaling pathways, scientists achieved that embryonic stem cells turned into cones.
However, what are the advantages of this method over the use of induced pluripotent stem cells obtained from the skin of the patient himself remains the biggest question.
The results of this study (Zhou et al., Differentiation of human embryonic stem cells into cone photoreceptors through simultaneous inhibition of BMP, TGFß and Wnt signaling) are published in the latest issue of the journal Development.
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07.10.2015