Cerebral organoids are arguably the coolest thing happening in neuroscience. It all starts with pluripotent stem cells – which are an amazing advancement in their own right. These are adult cells that have been genetically modified to behave as stem cells. Ever wonder why the debate over the ethical ramifications of using embryotic stem cells ended? Pluripotent stem cells are the answer. They have the ability, and flexibility, to grow into any type of adult cell, rendering the necessity of using embryonic stem cells obsolete in many instances.
The pluripotent stem cells are then used to grow teeny tiny tissue samples, in our case brain-like tissue samples, in vitro. The idea is that a simplistic model of the tissues and cells of the brain in a petri dish is much easier to study than the real thing – a complicated mesh of tissue and blood pulsating underneath a protective skull. According of a recent study highlighting the many potential uses of cerebral organoids: “Cerebral organoids contain many of the cell types found in embryonic cerebral cortex, organized in a similar way.” In addition, since these organoids have been grown from human stem cells, they may shed light on pathways and processes that differ between rodents – which are often the animals of choice in neurological research – and primates.
Cerebral organoids are already being used to bolster human health research. In order to study the impact of the Zika virus on the human brain, researchers injected the virus into brain-like organoids. The results were largely as expected: the infected tissues grew to be 40 percent smaller than the control tissue. Given the simplistic nature of, and easy access to, these infected organoids scientists were able to identify cell death as a mechanism of the virus and even pinpoint specific genes and pathways thought to be involved. This level of understanding could not have been achieved as quickly without using cerebral organoids as models.