Stem Cells Assemble Early Stage Human Brain

The internet and media that cover medical news have been buzzing about a story, published in the peer-reviewed journal Nature, reporting that researchers using stem cells have created a “mini-brain.” Researchers found that stem cells were able to assemble themselves into tiny clumps of complex neural tissue that they termed “cerebral organoids.” These structures resembled developing regions of the brain and were able to interact.

Researchers from the Austrian Academy of Sciences, the University of Edinburgh, the Wellcome Trust Sanger Institute and St. George’s University, London carried out the study. What they were trying to do was create a model of the human brain at its very early stages.

The researchers took human stem cells, derived from either embryonic stem cells or adult skin, and supplied them with nutrients and oxygen to support their development into brain tissue and structures. They were able to identify tissues similar to several developing brain structures, including the:

• cerebral cortex – the outer layer of the brain, which plays an important role in higher brain functioning
• choroid plexus – a structure ultimately responsible for the production of cerebrospinal fluid that surrounds and supports the brain
• retina – the light-sensitive tissue at the back of the eyes
• meninges – the membranes that surround the brain and spinal cord

The researchers also found that the cerebral organoids displayed key features of human brain development including patterns of cell organization expected to be seen during the early stages of development.

The tissues grew for approximately two months with the organoids reaching a maximum size of approximately 4mm in diameter. Although growth stopped, the tissue continued to survive up to ten months when the study ended. The researchers think that the lack of continuous growth is likely because of the lack of a circulatory system. They believe that their study represents “a novel approach for studying human neuro developmental processes”—how the human brain develops.