Eye factory from stem cells
For the very first time, an eye has been created from mouse embryonic stem cells. The announcement came from Japan and the potential implications of the research earned it the front cover of the prestigious magazine “Nature”.
The research opens up interesting prospects for treating serious degenerative eye diseases: if the experiment is successfully repeated with human stem cells – which is anything but impossible – “spare” retinas for replacing old ones could be created in the laboratory.
What struck scientists more than the mouse proto-eye or the idea of creating a retina “factory” was the extraordinary capacity of embryonic stem cells to self-generate. The mouse cells were able to self-organize and reassemble in different structures to create a complex organ. The only activity done by the team of development biologists, bioengineers and biochemists headed by Yoshiki Sasai at the Riken Center in Kobe was to grow mouse embryonic stem cells in a nutrient-rich solution that pushed them into spontaneous self-organization. Like the numerous small pieces in a puzzle, they formed the three-dimensional structure called “optic cup” in which the retina develops. This complex element consists of an outer and inner layer of tissue that folds in on itself during embryo development.
The exceptional feature of this research is the discovery that primitive stem cells are self-generating and do not need biocompatible “scaffolding”, the indispensable structures for scientists trying to create new organs in the laboratory. So far, at least, no one has been able to create a complex organ from a handful of albeit embryonic stem cells without the help of a culture medium. Japanese researchers have demonstrated that no support is required for the eye because the embryonic stem cells are self-organizing, almost as if they had innate “instructions” to be followed to the letter.
“This spontaneous self-organization amazed us” – the researchers said - “because the structure begins like a homogeneous aggregate of cells which is given no specific signal by us. The research shows that the formation of the eye is dependent only on the cells’ intrinsic program that directs the position and differentiation of each element”.
The discovery could open a new chapter on regenerative medicine, even though science has taught us that animal stem cells behave differently from human ones. The next step is to understand how. “It is still fairly unclear” – they wrote – “how individual parts self-organize to create an organ”. It will take many more years before an in vitro eye can be created for humans. Nonetheless, the fact remains that an important step forward has been taken. “It is exciting to think that we are on the right road for generating not only different cell types” – Sasai concluded – “but also tissues starting from stem cells and iPSC, induced pluripotent stem cells.”
(Source: La Stampa)
