For the first time, scientists have grown 3D models of the brain using cells from multiple people. The new hybrid creations, which the researchers call “chimeroids,” are a type of brain organoid—tiny 3D tissue models that mimic the structure and function of a full-size brain. These models are more accurate to human biology than 2D cell models or animals like lab mice, and the scientists hope the models will speed up research and drug development.
Typically, brain organoids are grown from cells collected from only one donor, meaning they don’t capture the genetic variation that exists between people, which can affect how a person’s brain develops and responds to medications.
Creating chimeroids could overcome this obstacle, according to the scientists behind the new study, published June 26 in the journal Nature. Such a “village in a plate” could be particularly useful in the early stages of drug testing, they say. Researchers have previously grown sheets of brain cells from stem cells taken from different people, but this is the first time 3D brain models have been grown in this way.
“Chimeroids are an exciting tool that will be used broadly in the field of neurodevelopment, likely with a variety of applications,” Aparna Bhaduri, an assistant professor of biological chemistry at UCLA who was not involved in the research, wrote in the article commenting on the study.
To create the chimeras, the researchers collected stem cells from five people, then used growth-promoting chemicals in the lab to encourage them to develop into brain organoids, each containing cells from only one person. The scientists then broke apart the resulting organoids and recombined the cells inside them to form chimeroids. This ensured that each chimeroid contained the same number of cells derived from each individual.
After three months, the chimeroids were about 0.12 to 0.2 inches (3 to 5 millimeters) in diameter and contained the same types of cells normally found in the cortex. — the outer layer of the fetal brain.
The team also exposed the chimeroids to two neurotoxic chemicals: ethanol, which has been linked to fetal alcohol spectrum disorders, and the anti-epileptic drug valproic acid, which can increase the risk of birth defects. The team found that cells from different donors responded differently to these drugs, for example, how much the chemicals inhibited their growth.
Scientists said that if chimeroids were scaled up to include cells from more people, it could theoretically help determine how patients respond to drugs before they are tested in clinical trials. These could then be divided into specific treatment response groups.
“I’m excited about what the future holds in terms of using organoids, such as chimaeras, to develop entirely new ways to achieve therapeutic innovations for neurological diseases,” Paola Arlotta, co-author of the study and a professor of stem cell and regenerative biology at Harvard University, told Live Science in an email.
Source: Port Altele
