Q&A - Revolution for brain research: new mini-organs

An organoid is a kind of 3D mini-organ. It is grown in the lab from cells of the human body. In this case: brain cells. An organoid allows scientists to mimic the functioning of a real organ in the lab. With the mini-brain, new research can be done on how the brain works. For example, how they develop. Or what happens when that development goes wrong - for example, with a brain tumor. These organoids are also important in studying the treatment of diseases related to brain development.

No. The mini-brains are grown from small pieces of a developing human brain. They are pieces from a specific part of the brain. A complete brain in a human being is very complex, with different areas connected to each other. So this is not the case with the mini-brains.

The mini-brains as currently developed remain at the same stage of development as the piece of brain from which they were grown. Researchers can encourage them to mature further; then they acquire characteristics of a later stage of development. That could be important for better understanding brain development. It is not yet known whether there will be a limit on maturation. That is one of the issues a bioethicist is thinking about.

3D mini-organs are grown from two different sources. The first are so-called pluripotent stem cells - these are special cells that can still grow into many other types of cells. The second is human tissue - from a fetus or an adult. These two types of mini-organs have different advantages, and thus complement each other well as "tools" for scientific research.

Until now, it had not been possible to make brain organoids from tissue. In the new study, it has succeeded. The advantage is that all the different brain cells in the mini-brain developed naturally. The instructions of which cell type to become came from the tissue itself, and was not directed by the researchers. Therefore, these self-organizing organoids could help researchers answer other, new questions about how the brain - and brain diseases such as brain tumors - develop.

The tissue came mostly from planned abortions. The tissue came from healthy abortion material, from gestational weeks 12 to 15, from completely anonymous donors. The anonymous women donated the tissue voluntarily and with informed consent. The donors knew the material would be used only for research purposes. They had been told that the research could be on understanding normal organ development, including the possibility of growing cells from the donated material.

The reason for using abortion tissue from this stage was primarily biological. New nerve cells develop at this stage of development. This is a very interesting stage to study neural stem cells and how they develop into different types of neurons. The researchers think it is also possible to grow organoids from other stages of development. That could provide information about the different steps that take place during brain development. Therefore, they are keeping this in mind for future research.

This is a complex question that is controversial within the research community. However, we do know that it is likely that consciousness is acquired after birth. A developed neural system is necessary but not sufficient for pain experience, since development of the mind is necessary to understand the subjectivity of pain. Some studies suggest that developing of the sensory nervous system associated with pain sensing can start at around 26 weeks in pregnancy, but still, the pain sensing experience as children and adults is related to consciousness, something that begins only after birth.

They can, after ethical approval and approval of their research by the relevant committees. Access to fetal material is limited. With the research, the scientists are also providing a way to multiply this precious material. This allows the research community to make the best use of it which may result in important new findings about brain development and brain diseases.

Not necessarily. For some organs, there are major differences between human and animal models. For example, there are major differences between human brain development and brain development in mice: different cell types are involved and different genes are important. So in brain research, human models are of great importance. But animal models have also been invaluable and will continue to be so in the future.

There is a big difference between a model in a dish, however accurate, and a living organism. Research with organoids is appropriate for different research questions than animal models. For example, you cannot study the interaction between different organs with organoids; that requires animal experiments. Also, effects of drugs or other substances on the whole body still require animal experiments.

Read more about our research with laboratory animals here.