Mini Human Brain Grown In Petri Dish

  Brain Research  

Scientists in Austria have grown a three-dimensional, self-organizing model of a developing human brain in the lab using stem cells. The mini-brain may help research brain diseases and treatments more effectively.

Researchers at the Institute of Molecular Biotechnology in Vienna, Austria, have grown a three-dimensional, self-organizing model of a developing human brain in the lab using stem cells.

The system could be used to model neurological diseases and test treatments in an actual human brain, instead of an animal model that may not develop in exactly the same way, or in human patients.

The cerebral organoid, as the researchers have called it, resembles the early developing regions of a human brain, with distinct regions like the dorsal cortex, the ventral forebrain and even an immature retina.

This is the most complex in vitro human brain tissue created so far. It has the beginning signs of cortical layers, though it can't develop the full complexity of a six-layer human cortex.

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The scientists were able to grow their organoids from both embryonic stem cells and the less-controversial induced pluripotent stem cells, which can be derived from the skin or blood cells of adult humans. Most of the organoids grew to about 3 or 4 millimeters, about the size of an embryonic human brain at roughly nine weeks, and could survive up to a year in a spinning bioreactor (to circulate nutrients and oxygen).

Though it looks very similar to early-development brain tissue and has active neurons, the organization isn't quite the same as in naturally developing tissue.

Using imaging techniques, the researchers were even able to detect neural activity (see video, above), although this doesn't mean the brain is conscious in anyway.

"The parts are correctly organized, but not put together," Jürgen Knoblich who coordinated the study, explained in a press conference. He describes it as "a car where you have an engine, you have the wheels--but the engine is on the roof…that car would never drive, but you could still take that car and analyze how an engine works."

The stem-cell-derived organoid (right) compared to a developing mouse brain (left)
 Image Source: Marko Repic and Madeline A. Lancaster) 

Scientists have been able to grow other organ tissue in the lab with stem cells, like livers and heart tissue. Unlike with other lab-grown tissue, though, synthetic brain transplants or patches aren't really on the horizon here. The brain is just too complex, for one, and the lack of circulatory system makes it difficult to get enough nutrients and oxygen to the organoid tissue to grow it any larger than 4 millimeters.

Even though they're not exactly put together like human brains, cerebral organoids could be used to analyze diseases like microcephaly, a neurodevelopmental disorder that results in severely small brains.

"Recent work has shown development of human brain is very fundamentally different from the development of the mouse brain," Knoblich said, and certain diseases like microcephaly have been hard to replicate in mice. "Our system is very useful for us as developmental biologists. It allows us to study the human-specific features of brain development." Eventually he would like to be able to model disorders like schizophrenia or autism.



SOURCE  New Scientist

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