Lab-grown organoids are more stressed-out than actual brain cells
Brainlike clumps of cells don’t behave like cells taken from tissue
CHICAGO — Brain cells grown into clumps in flasks are totally stressed-out and confused. Cells in these clumps have ambiguous identities and make more stress molecules than cells taken directly from human brains, researchers reported October 22 at the annual meeting of the Society for Neuroscience.
These cellular clumps are grown using stem cells made from skin or blood, which under the right conditions can be coaxed into forming three-dimensional clusters of brain cells. These clusters, a type of organoid, are thought to re-create some aspects of early human brain development, a period that is otherwise difficult to study (SN: 2/20/18).
The new results highlight underappreciated differences between these organoids and the human brains they are designed to mimic. “Most of the papers out there are extolling the virtues of these things,” says study coauthor Arnold Kriegstein, a developmental neurobiologist at the University of California, San Francisco. But the new study reveals “significant issues that nobody has addressed yet.”
Kriegstein and colleagues compared genetic activity in human cells from brain tissue in early development with human cells grown in an organoid. Cells in the organoids had more active genes involved in stress responses. What’s more, these organoid cells didn’t fit into the neat categories of cells in actual brain tissue. Instead, some of the organoid cells showed features of two distinct categories simultaneously. “They are not normal,” Kriegstein says.