Rise Of The Organoids: Miniature Human Brain Most Complete To Date

Lab-grown brain is labeled to show identifiable structures: the cerebral hemisphere, the optic stalk and the cephalic flexure, a bend in the mid-brain region, all characteristic of the human fetal brain. Courtesy: The Ohio State University

As regenerative medicine expands, our ability to engineer organs is growing with it. Researchers can now grow a number of so called ‘organoids‘ – mini-organs which can teach us more about developmental biology and enable vastly improved testing. In the latest addition to the bunch, a team from Ohio State University has successfully engineered the most complete model yet of a human brain, with a similar maturity to a 5 week old fetus. 

Containing 99% of the genes present in the human fetal brain, and about the size of an eraser, the organoid was developed from transformed adult human skin. This method could allow more ethical and precise clinical trials, both speeding up and enabling more rigorous, personalized testing. As animal testing frequently fails to predict varied human responses, these organoid models offer an alternative approach which could revolutionize clinical trial methodology. 

“It not only looks like the developing brain, its diverse cell types express nearly all genes like a brain. We’ve struggled for a long time trying to solve complex brain disease problems that cause tremendous pain and suffering. The power of this brain model bodes very well for human health because it gives us better and more relevant options to test and develop therapeutics other than rodents.”

Although the model is missing a vascular system, it contains multiple brain regions, a retina, circuitry and even the beginnings of a spinal cord. It’s not absolutely ‘complete’, but it’s certainly more so than ever before. 

An Intestinal organoid. Could similar models soon be common in medicine?

“In central nervous system diseases, this will enable studies of either underlying genetic susceptibility or purely environmental influences, or a combination. Mathematical correlations and statistical methods are insufficient to in themselves identify causation. You need an experimental system – you need a human brain.”

The project is also another success story for induced pluripotent stem cells; creating a range of neural tissue via various differentiation techniques. It currently takes 15 weeks to reach this defined stage, but researchers suggest that if the model was left even longer, further maturation might be observed. 

“If we let it go to 16 or 20 weeks, that might complete it, filling in that 1 percent of missing genes. We don’t know yet” 

Read more at NeuroScientistNews