Growing simplified, miniature versions of human brains in the lab can provide researchers with an invaluable model for studying cognitive disorders and how disease takes hold in this incredibly complex organ, and recently we're seeing how these organoids share some striking similarities with the real thing. Scientists have carried out a first-of-a-kind analysis of 20-month-old lab-grown brain organoids to find that they had matured much like a human brain, following an internal clock to guide their development.
Lab-grown brain organoids are gaining in prominence as a research tool, providing scientists with a platform to study disorders like epilepsy, autism and schizophrenia, or even test out the impacts of psychedelic drugs on different proteins. We've also seen how these organoids can sprout their own blood vessels, and give off electrical signals akin to the brain of a preterm baby, shedding light on how they might develop characteristics similar to that of human brains.
It all starts with induced pluripotent stem cells, which are subjected to specific chemicals that cause them to mature into different types of brain cells. This sees them assemble themselves into 3D structures that replicate those found in the brain, and while this doesn't result in consciousness, the structure does play host to electrical signals that travel around in much the same way as they do in the human brain.
In this novel study, scientists at Stanford University and the University of California, Los Angeles grew these organoids in lab dishes over the course of 20 months. The researchers then used genetic analysis to investigate the rate of development, finding that these lab-grown mini-brains had reached postnatal maturity in 250 to 300 days, a "timeline paralleling in vivo development."
"We show that these 3D brain organoids follow an internal clock, which progresses in a laboratory environment in parallel to what occurs inside a living organism," says first author on the study, Aaron Gordon. "This is a remarkable finding – we show that they reach post-natal maturity around 280 days in culture, and after that begin to model aspects of the infant brain, including known physiological changes in neurotransmitter signaling."
The reason these findings are so significant is because until now, the common perception around lab-grown brains was that the cells don't generally develop past the stage equivalent to fetal development (with the preterm-baby-like electrical signals mentioned above a notable exception). This kind of research therefore raises the prospect of lab-grown brains one day maturing even further, which would open up entirely new avenues for scientists to study adult-onset diseases, like schizophrenia and dementia.
"This is novel – until now, nobody has grown and characterized these organoids for this amount of time, nor shown they will recapitulate human brain development in a laboratory environment for the most part," says study senior author, Daniel Geschwind. "This will be an important boost for the field. We've shown that these organoids can mature and replicate many aspects of normal human development – making them a good model for studying human disease in a dish."
The research was published in the journal Nature Communications.
