This is an exciting year for developments in stem cell research. So far we’ve seen a miniature but functional human liver, the ‘Google Burger’, and now another mini but major organ. Scientists at the Institute of Molecular Biotechnology at the Austrian Academy of Sciences have reproduced the early stages of brain matter.
Using embryonic and adult skin cells, the neuroscientists have grown a neuroectoderm – the embryonic matter that develops to become the brain and spinal cord. The cells were initially placed in a culture dish and then a gel support structure, before finally being placed inside a spinning bioreactor that “constantly agitates the medium and agitates the organoids inside to allow for better nutrient and oxygen exchange.”
The cells arranged themselves into separate brain regions, such as the cerebral cortex, the retina and even an early hippocampus, the area of the brain responsible for memory function. These brain samples, complete with active neurons, were authentic for nine weeks before the developmental path diverted from that of a regular human brain.
In testing, some brain organoids continued to grow for up to a year, but never exceeding the four millimetres reached at nine weeks.
Without the support of a true circulatory system, complete with blood vessels and rich in nutrients and oxygen, the growth process of the “mini brains” is halted. One of the researchers, Dr Juergen Knoblich of the Institute of Molecular Biotechnology in Vienna, said: “What our organoids are good for is to model development of the brain and to study anything that causes a defect in development.
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Ultimately we would like to move towards more common disorders like schizophrenia or autism. They typically manifest themselves only in adults, but it has been shown that the underlying defects occur during the development of the brain.”Previously,
human stem cells have been harvested into layers of tissue resembling the brain’s cortex, but this is undoubtedly the next major development in human stem cell research.
The study opens the forum for neurological disorder research using stem cells. Indeed, the researchers used this study to replicate facets of the neurodevelopmental disorder Microcephaly, which causes cognitive impairment and stunted brain growth in humans. The findings mostly confirmed current theories about the disorder, with stem cells taken from a person with Microcephaly lagging behind those collected from a person not afflicted, in growth terms.
At this point there are no concerns over ethics, as the brains are still far off consciousness or awareness, but obviously this will have to be monitored with any future advancement. Because of this, however, the potential to study diseases other than developmental is not yet clear, and neither is the possibility of drug-testing. Brain-affecting drugs and mental health disorder treatment, for instance, are often based on factors including mood, pain and perception, so without the presence of conscious thought, it will not be possible to use this research model for such investigations. Dr Martin Coath, from Plymouth University’s Cognition Institute said “Any technique that gives us ‘something like a brain’ that we can modify, work on, and watch as it develops, just has to be exciting.” If progress in stem cell research continues at this rate, these types of studies could soon become reality.