A new study conducted by researchers of the Institute Riken in Saitama (Japan), shows that the use of tissue of the retina derived from induced pluripotent stem cells (iPS) is effective to the hour to restore visual ability in animal models –mice– with dystrophies of the retina in advanced stages or 'terminal' –that is, when the external plexiform layer, the photoreceptor cells connect with the optic nerve, has already disappeared, reported ABC.
The transplantation of tissue of the retina instead of using only photoreceptor cells allows the development of a morphology more organized and mature of the retina, which leads to a better response to light, said Michiko Mandai, co-author of this research published in the journal Stem Cells Reports.
The iPS are a type of stem cells, obtained from reprogramming to an embryonic state of any particular cell –for example, of the skin, have the capacity to differentiate into any cell of the body –in this case, the retina–. As well, and in the first place, the authors 'manufactured' layers three-dimensional images of the retina from iPS of mice and transplanted them into the animals.
The transplantation of photoreceptor cells of donors, although they may partially restore the function of the retina, fail to integrate properly in the eye of the receiver. As a result, these grafts do not establish the necessary synaptic connections to send the visual signals from the retina to the brain.
in order to evaluate the effectiveness of the new procedure, the authors, led by Masayo Takahashi, attached a fluorescent protein to the terminal end of the photoreceptor cells, that is to say, to the end that these neurons are connected to bipolar cells that, in turn, come into contact with the horizontal cells that form the optic nerve. And what they saw with this fluorescence technique is that, effectively, the new photoreceptor cells connect to bipolar cells, thereby ensuring the communication between the retina and the brain.
Finally, the researchers evaluated whether the procedure was effective for restoring, at least partially, the vision of the mice. And for this, they used light stimuli, and observed whether the animals responded in a way expected to how they would do those with normal vision. Logically, the mice that had not received the transplant were unresponsive to these stimuli. On the contrary, those intervened reacted predictably to the light signals, which indicated not only that the new cells of the retina responded to light, but that the information was being transported to the brain.
In short, the new procedure opens up a pathway for the restoration, by order, of the vision in people affected by dystrophies of the retina.
“Our findings are a 'proof of concept' for the use of tissue of the retina-derived iPS for the treatment of dystrophies of the retina. So, we’re already planning for the launch of human clinical trials, for which we must perform more studies using tissue of the retina derived from human iPS in animal models. And is that clinical trials are the only way to determine how many new connections are needed for a person to be able to 'see' again,” added Michiko Mandai.
In consequence, you still will have to wait. In addition, and given that the procedure is still in a very early stage of development, the authors ask for caution.
we Still can not expect that we will be able to restore vision. We will start with the possibility of seeing a single light, to then continue with and to strive for the vision of figures of great size in a later stage, concluded the researcher.
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