Pea-sized human brains grown from stem cells

For the first time, researchers have successfully created living, growing, miniature human brains in a controlled environment. The aim of the experiment is to gain new insights into brain development and structure. It is hoped this will lead to the knowledge of what occurs in a growing human brain that leads to malfunctions such as autism and schizophrenia.

The laboratory-grown organs are approximately the size of a small pea. There development has been compared to that of a 9-week-old fetus. The brains, are, however, not capable of any thought, according to the scientists involved.

Scientists working in Austria began with human stem cells. From these a culture was started that was able to be grown into what they call ‘cerebral organoids’. This is their description of small brain-like cultures. These contain a portion of the total number of different brain areas normally found in a functioning human brain.

This accomplishment marks the initial success at simulating human brain growth with 3-dimensional neuroectoderm tissue. This is the same tissue that grows in an embryo to become the human brain and nervous system. Pieces of this brain tissue were held in a scaffold-like device, which was placed in a bioreactor. This apparatus spins, dispensing and dispersing nutrients and oxygen to the organoids. Within 30 days, the tissue pieces had aligned into simple organized structures. Within this growth, separate choroid plexus, cerebral cortex and retina divisions could be detected.

The small brain growths have now grown for almost one year, but are no longer getting larger, or become more organized or complex. No blood is being supplied to the organoids, just additional brain tissue. No food or oxygen is able to be delivered into the center of the tissue mass.

All scientists questioned were of the opinion that while this is a momentous and exiting accomplishment, the ability to grow a completely functional human brain is still a long way away.