German scientists have learned how to obtain "in vitro" the embryos of brain structures with optic cups capable of reacting to light.
Organoids are miniature, artificially grown "blanks" of organs. They make it possible to conduct research and experiments that cannot be performed on real living organisms, and at the same time consider processes that are inaccessible when using individual cells and cell cultures. Organoids are three-dimensional structures of specialized cells grown "in vitro" from stem cells. From them, for example, analogs of the human brain are obtained by observing the spontaneous activity of tiny clumps of neurons and discussing whether they might turn out to be intelligent.
Scientists from the Clinical Hospital of Dusseldorf, led by Jay Gopalakrishnan, also worked with brain organelles. They found that some of the structures grow a pair of symmetrical optic cups - the embryos of future eyes. In itself, this is quite logical, because the visual apparatus in embryos is formed from the outgrowth of the nervous system. However, scientists have not met with anything like this before and now they hope that with the help of such "big-eyed" organelles it is possible to better investigate the processes of eye formation and their diseases. They write about this in an article published in the journal Cell Stem Cell.
Previously, biologists were able to grow cups from pluripotent stem cells. But Gopalakrishnan and his colleagues decided to go indirectly, having received these structures as part of a holistic system integrated with the brain organoid - closer to how everything works in a living organism. To do this, scientists made changes in the method of growing the organoid and did not stimulate the development of neurons from the very beginning of cultivation. In addition, retinol was added to the solution, which promoted the formation of cells of the visual apparatus.
Eye cups appeared in 73 percent of the 314 organelles grown. Their formation began on the 30th day, and on the 50th they were already clearly distinguishable. At the same time, this happens during the maturation of the embryo. Moreover, the resulting structures contained the rudimentary lens and cornea, as well as various retinal cells, which allowed them to respond to light. Finally, they began to form connections with the cells of the brain organoid itself. Previously, scientists could not see anything like this "in a test tube."