Scientists are growing tiny clusters of brain cells- referred to as “minibrains” - in petri dishes to observe the effects of viruses. It’s hard to study the effect of neurotropic viruses in vivo, so the minibrains help enormously with looking at emerging viruses like Zika, which can have devastating effects on fetuses.
Minibrain cells start as epithelial cells (like skin cells) and scientists use molecular techniques to turn these cells into neural stem cells, which ultimately differentiate to cells found in the brain. The ultimate product is, well, “mini”… the minibrains can fit on the head of a pin. One useful aspect of the final minibrains is that they imitate real brains’ connectivity. The minibrains have network connectivity and communication between cells, similar to what you might find in a real brain. This provides a more realistic environment for scientists to study viral effects than in simple cell culturing methods. Additionally, their small size allow scientists to keep many minibrains at one time and use many replicates in studies.
Currently, researchers at Johns Hopkins are looking at how Zika virus affects the minibrains. They can reveal how the virus affects brains that are developing- much like how fetal brain tissue does in the first trimester of pregnancy. They’ve observed that the minibrains decrease in size when exposed to Zika- mirroring how infected babies are born with a shrunken brain.
Research with minibrains is still evolving. Many would like to use them in new studies on neurodegenerative disease and drug development. There are many human viruses that may have neurological effect that could be investigating further using this method.