Skip to main content
Part of complete coverage on

Scientists grow mini brains from stem cells

By Elizabeth Landau, CNN
updated 11:24 AM EDT, Wed October 2, 2013
In January 2014, researchers announced they had developed a new method of making stem cells -- by placing skin cells in an acidic environment. But the researchers retracted their papers in July 2014, citing "several critical errors" in their study data. Click through the gallery to learn more about stem cell research. In January 2014, researchers announced they had developed a new method of making stem cells -- by placing skin cells in an acidic environment. But the researchers retracted their papers in July 2014, citing "several critical errors" in their study data. Click through the gallery to learn more about stem cell research.
HIDE CAPTION
History of stem cells
History of stem cells
History of stem cells
History of stem cells
History of stem cells
History of stem cells
History of stem cells
History of stem cells
History of stem cells
History of stem cells
History of stem cells
History of stem cells
History of stem cells
History of stem cells
History of stem cells
<<
<
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
>
>>
STORY HIGHLIGHTS
  • Researchers used stem cells to make organoids
  • These organoids can be used to explore brain development
  • Parts in organoids resemble brain regions in a 9-week-old human embryonic brain
  • Embryonic and induced pluripotent stem cells yielded the same results

(CNN) -- We've seen beating heart tissue, windpipes and bladders all grown from stem cells. Now researchers have taken another important step forward by growing mini brains from these programmable cells.

They're not actually functioning brains -- in the same way that a car with the engine on its roof or wheels on its hood isn't a drivable vehicle -- but the parts are there, and that's an important scientific advancement, according to Juergen Knoblich, senior author of a new study on using stem cells to grow brain tissue.

Scientists have created what they are calling "cerebral organoids" using stem cells. These pea-sized structures are made of human brain tissue, and they can help researchers explore important questions about brain development and disorders that occur during these first stages of life.

The organoids, as described in the journal Nature, have components resembling those of a brain of a 9- or 10-week-old embryo, said lead study author Madeline Lancaster, a researcher at the Institute of Molecular Biotechnology at the Austrian Academy of Science in Vienna, at a press briefing Tuesday.

She and colleagues have created hundreds of these organoids.

Tasters: Stem cell burgers a bit 'dry'
Understanding the stem cell breakthrough

At this early stage of human development, several key regions of the brain are already distinctive features, including the dorsal cortex, the ventral forebrain, the choroid plexus -- which generates cerebrospinal fluid -- and regions that resemble the midbrain and hindbrain. Lancaster and colleagues say they've identified some of those same regions in these new mini brains.

However, these regions did not naturally fall into place in the stem cell models the same way they would have in a normal brain.

"These different regions are not organized in the same kind of fashion that you would see in the developing embryo," Lancaster said.

The organoids also lack certain features that human embryonic brains at 9 weeks do have: most importantly, the cerebellum, which is involved in motor movement. Also, the hippocampus, a seahorse-shaped structure crucial for memory, was rarely detected in these brain-like structures.

Researchers used human embryonic stem cells and induced pluripotent stem cells (IPS cells) for this research. Both embryonic stem cells and IPS cells have the ability to turn into any part of the body. But embryonic stem cells are very controversial because in the process of retrieving them for research, the 4- or 5-day-old embryo they are taken from is destroyed. IPS cells don't come with the same controversy because scientists take a cell -- typically a skin cell -- then coax it using a chemical bath to revert to a state that resembles a developing embryo.

There did not appear to be an obvious difference between organoids derived from embryonic stem cells and those produced from IPS cells, said Knoblich, also of the Austrian Academy of Science.

Study authors found variability in the organoids they generated; occasionally some of the brain regions they were studying failed to appear.

Lancaster attempted to direct the development of these regions in some of the organoids by applying growth factors, substances that promote the proliferation of cells. Surprisingly, when she tried to grow the mini brains with more dorsal cortex tissue, the resulting structures had less of this tissue than the organoids that had developed on their own.

"We actually think that the cross-talk between these different regions -- the communication between these different brain regions within the organoids -- is really important for each individual region's development," she said.

The researchers used this model to look at a neurodevelopmental disease called microcephaly, a disorder in which the size of the brain is reduced. The brain region they were most interested in exploring, the dorsal cortex, is the region most highly impacted by this disease.

Researchers grew some of these organoids using cells from a patient who had a genetic form of microcephaly, and compared them with the mini brains derived from healthy participants' cells.

In the organoids made from the microcephaly patient's cells, it appeared that more stem cells had been turned into neurons -- a process called differentiation -- than in the mini brains derived from healthy patients' cells. This suggests that in people with this condition, neurons prematurely differentiate, which could be the mechanism behind this form of the disease, said Oliver Brustle at the Life & Brain Centre at University of Bonn, in an accompanying article in Nature.

This research builds on other studies that have attempted to model brain tissue from stem cells. A 2008 study showed that mouse embryonic stem cells could be coaxed into producing "waves" of neurons. A different research group showed in 2012 that primitive eye structures and stratified retinas could form from embryonic stem cells taken from both mice and humans. Study authors said they have no intention of growing a full-sized human brain.

"It is very clear that our system is not optimized for generating an entire brain, and that is also in no way our goal," Knoblich said.

As for growing a brain structure from stem cells that's capable of conscious thought, Knoblich said this would likely not be possible, or desirable.

Although the organoids are an important step forward, the researchers are nowhere near being able to model circuits found in the functional central nervous system. Moreover, Knoblich said, sensory input is required for such functional circuits to form. A classical experiment showed that the optic cortex will not organize properly if it does not have input from an eye, he said.

Knoblich is also pessimistic about the idea of growing brain structures from stem cells with the intention of replacing faulty ones in human patients. The brain is so complex, and its regions so intimately integrated, that it would be difficult to repair any specific part through substitution.

A more promising possibility, he said, would be to put the stem cells directly into the patient and let them organize themselves. But the future of this line of research is still unknown.

Brustle, who was not involved in this research, called the study "remarkable" and noted that it "clearly puts neural aggregation cultures on the map of research tools for both developmental biology and biomedicine."

That's a lot from a little tissue.

Follow Elizabeth Landau on Twitter and Google+.

ADVERTISEMENT
Part of complete coverage on
Science news
updated 7:52 AM EDT, Tue July 22, 2014
The world's largest flying aquatic insect, with huge, nightmarish pincers, has been discovered in China's Sichuan province.
updated 8:10 AM EDT, Mon June 23, 2014
As fans of "Grey's Anatomy," "ER" and any other hospital-based show can tell you, emergency-room doctors are fighting against time.
updated 7:59 AM EDT, Thu May 29, 2014
Ask 100 robotics scientists why they're inspired to create modern-day automatons and you may get 100 different answers.
updated 12:35 PM EDT, Fri June 13, 2014
From the air, the Namibian desert looks like it has a bad case of chicken pox.
updated 12:43 PM EDT, Wed May 28, 2014
The trend for nature-inspired designs has spread across industries from crab-style deep-sea vessels to insect-inspired buildings.
updated 8:22 AM EDT, Sun May 25, 2014
Consider it the taxonomist's equivalent of a People magazine's Most Beautiful List.
updated 11:32 AM EDT, Fri May 9, 2014
For the first time, scientists have shown it is possible to alter the biological alphabet and still have a living organism that passes on the genetic information.
updated 7:48 AM EDT, Mon May 5, 2014
Do we really want to go the route of "Jurassic Park"?
updated 8:44 AM EDT, Fri May 2, 2014
Catch a train from the sky! Perhaps in the future, the high-rise superstructures could help revolutionize the way we travel.
updated 10:58 AM EDT, Mon May 5, 2014
In a nondescript hotel ballroom last month at the South by Southwest Interactive festival, Andras Forgacs offered a rare glimpse at the sci-fi future of food.
updated 10:12 AM EDT, Thu March 20, 2014
For a Tyrannosaurus rex looking for a snack, nothing might have tasted quite like the "chicken from hell."
updated 6:29 PM EDT, Fri March 14, 2014
Everyone is familiar with Tyrannosaurus rex, but humanity is only now meeting its much smaller Arctic cousin.
updated 12:12 PM EST, Thu March 6, 2014
At about 33 feet long, weighing 4 to 5 tons and baring large blade-shaped teeth, the dinosaur Torvosaurus gurneyi was a formidable creature.
updated 6:43 AM EST, Fri February 21, 2014
This Pachyrhinosaurus can go to the head of its class.
updated 8:04 AM EDT, Thu March 27, 2014
Science is still trying to work out how exactly we reason through moral problems, and how we judge others on the morality of their actions. But patterns are emerging.
updated 7:06 PM EST, Thu February 27, 2014
A promising way to stop a deadly disease, or an uncomfortable step toward what one leading ethicist called eugenics?
updated 8:07 PM EST, Fri February 14, 2014
Seattle paleontologists safely removed the largest fossilized mammoth tusk discovered in the region from a construction site.
updated 6:13 AM EDT, Tue April 23, 2013
A mysterious, circular structure, with a diameter greater than the length of a Boeing 747 jet, has been discovered submerged about 30 feet underneath the Sea of Galilee in Israel.
updated 5:25 PM EST, Fri January 17, 2014
Every corner of the planet offers some sort of natural peculiarity with an explanation that makes us wish we'd studied harder in junior high Earth science class.
updated 8:20 AM EST, Thu November 14, 2013
Deep in a remote, hot, dry patch of northwestern Australia lies one of the earliest detectable signs of life on the planet, tracing back nearly 3.5 billion years, scientists say.
updated 3:10 PM EDT, Wed September 4, 2013
We leave genetic traces of ourselves wherever we go -- in a strand of hair left on the subway or in saliva on the side of a glass at a cafe.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT