LOS ANGELES — Scientists have figured out how to grow human stem cells into “cerebral organoids”: blobs of tissue that mimic the anatomy of the developing brain.
The advance, reported online Wednesday in the journal Nature, won’t allow scientists to grow disembodied brains in laboratory vats, said study leader Juergen Knoblich, a stem-cell researcher at the Institute of Molecular Biotechnology of the Austrian Academy of Science in Vienna.
But it does offer researchers an unprecedented view of human brain anatomy, he said. Having the ability to probe a 3-D model of a 9-week-old embryo’s brain could help scientists better understand conditions that have been linked to problems in brain development, including autism and schizophrenia.
In a first, Knoblich’s research team has already grown brain organoids using stem cells from a patient with microcephaly, a rare genetic disorder that stunts brain growth.
Scientists had been able to use stem cells to make neurons, gut tissue, pituitary glands, livers and rudimentary human eyes, Knoblich said. But they’ve never grown a proto-brain complex enough for its different regions to interact the way they would during early brain development.
The key was to seed the cells in a gel-based scaffold to support them as they grew into neural tissue and to bathe them in nutrients with a spinning device called a bioreactor. Following this recipe, the organoids grew to 3 or 4 millimeters in diameter, relatively large in embryonic-biology terms.
The hundreds of organoids the team made didn’t look like 9-week-old embryo brains, exactly, but they shared many key characteristics. The regions weren’t spatially organized as they would be in a developing embryo. But their presence in the organoid was enough to allow the team to study how neurons form in and migrate through the early brain.
“I often compare this to a car — you have the engine, you have the wheels, but the engine is on the roof,” Knoblich said. “The car would never drive, but you could take that car and analyze how an engine works.”
The group has no plans to try to generate a functional brain.
That would be extremely difficult and unethical, Knoblich said.