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For the first time, researchers 3D models of the brain created that contain various cell types from several people 1 . These "village in a bowl" organoid could help reveal why the brain's reaction to medication from person to person varies.

other teams have made 2D layers of brain cells more than a human donor 2 , but this work reports this work About robust 3D systems that are suitable for research.

"It is a really powerful technology and a performance scooter approach," says Tomasz Nowakowski, a biologist at the University of California, San Francisco, who was not involved in the study. Many groups will probably apply this method, he adds. "It's a technical masterpiece."

These chimera cultures called Chimeroids combine cells of up to five donors. Future versions could house cells from hundreds of people. "What if one day we could use Chimeroids as avatars to predict individual reactions to new therapeutic agents in a study before testing? was.

a village is needed

Model systems called organoids ahmen the cellular composition of organs like the intestine and lungs. Researchers create them by bathing stem cells of a human donor in a precisely formulated cocktail of chemicals, which stimulates the stem cells to develop in all cell types that are typically present in a certain organ. The cultural conditions also promote the meeting of the cells into a complex 3D form.

brain organoids are particularly slow to handle and difficult to handle, and researchers are looking for better methods to make them. One approach was to combine cells from several donors to a single organoid. Multi-donation cell piles could be easier to use and capture a wide variety of human genetics in a single model. However, since the starting stem cells grow at different speeds, inevitably rapidly growing lines.

from many, a

The trick, as Arlotta and her colleagues report, is to first produce a number of individual donor organoids. Since these tires, the cells take on similar growth rates in all organoids. By homogenizing these structures and summary of the cells, it is possible to breed an assembled organoid. The authors' chimeroids have expanded to about 3-5 millimeters after three months and contain the same cell types that are present in the fetal cortical tissue.

"This is a really great progress," says Robert Vries, managing director of the organoid research company Hub Organoids in Utrecht, Netherlands. The community that examines the central nervous system "really needs more organoid systems".

chimeroids should enable researchers to find out whether medication will have different effects on different people. As a test case, the team treated the multi-donation organoid with neurotoxic drugs. Ethanol, which causes fetal alcohol syndrome, reduced the number of cells from a single donor cell line. Cells of this donor grew faster when they were combined with valproin acid, an antiepileptic, which with an increased risk for Autism-Spektrum-Disorder In children who came into contact.

growth pain

However, careful follow -up work will be necessary to ensure that the effects observed in the chimerarian models come from the genetics of a certain cell line and not from an interaction between tightly packed cells, warns Vries.

Nowakowski, who examines the model in his laboratory, adds

chimeroids. But automated cell culture systems should make the workload easier and make these models suitable for more efficient experiments.