Miniature brains from stem cells : Lord, let the brain grow

"I Need today is a hat?" It is a simple, possibly not even loudly outspoken question. And yet, it triggers in the brain a fireworks display of electrical signals between nerve cells and chemical reactions. In a fraction of a second scenarios to be played in parts by: the hat to the otherwise cold ears talk, by contrast, the disheveled hair. But a cap is worth it even for the short way? What is the weather report says? Pictures and memories, information from the Long - and short-term memory, rated all retrieved, assessed, and finally decided For the red bobble hat.

more Difficult to look into the thinking organ

But what if the brain is functioning as it should? If the cap decision is insoluble, or a mania? In order to develop drugs and therapies for mental or other brain diseases, it is important that the thinking organ. However, it is not so easy. Finally, researchers can view the internal structures of the human brain, only then, if the person has died. Imaging techniques such as functional magnetic resonance imaging (fMRI) allow an insight in the living brain without harming the patient. But the insights are limited, especially since it is not the nerve cells themselves, but their actual nutrient consumption when Thinking is measured. Also the view of the human-like brains of mice, rats and other experimental animals has its limits. Many of the "typical human" diseases – such as schizophrenia or psychosis in animals, neither good adjustment nor understand. This is probably one of the reasons why promising drugs in patients is not, hardly or different, although they worked in animal experiments. Many pharmaceutical companies have to diseases, the search for active substances against dementia, or other brain, therefore, abandoned.

Organoid laboratory versions of human organs

A new way to get insight into the functions and malfunctions of the human brain, are Organoids from human stem cells cultured in three-dimensional Structure of brain tissue. "We hope that the Organoid technology are revolutionizing our understanding of developmental processes and diseases of the human brain and will help to find new drugs against diseases of the human brain," says Julia Ladewig, head of the Organoid research from the Hector Institute for Translational brain research at the Central Institute for Mental health in Mannheim.

Indeed, the Organoid-tissue breeding for the exploration of many other organs of the human body are already proven: There are both liver Organoids, as well as miniature editions of the kidney, the retina in the eye, as well as of organs of the digestive tract such as the pancreas. Last week, researchers at the University of Cambridge reported in the UK, even on an Organoid of the placenta, the structure of supply between the mother and the Embryo, an Organ, the brain, can be otherwise difficult to "live" and explore. In fact, the development of three-dimensional Mini-organs for research is so groundbreaking that the journal "Nature Methods" chose you in 2017, the "method of the year". Especially the possibility of thousands of active substances to the human Mini-organs for testing and not testing on animals depend, is progress.

Can develop cerebral Organoid, a human consciousness?

So practically a miniature human brain in a Petri dish, however, may be to be able to about the interaction of nerve cells to investigate the patients with schizophrenia in the suspicion of the disease to trigger. When the thinking organ is also the ethical Dimension must be considered. The fact scientists themselves point to the 17 leading neuro: ethical guidelines for experiments with brain organo-had to be identical, write in a commentary in the journal "Nature". And quickly. Still brain organoids were only a collection of which can not feel or think. However, it is anticipated that further developments to the fabric of breeding will lead to you become more and more complex. The experts, including the geneticist George Church and the neuro-scientist Steven Hyman, both of Harvard University, therefore, ask themselves whether the potentially (self-)conscious cell clusters also should have rights, such as human or animal Subjects.

"We do not believe that this research should be stopped because of these difficult questions. But to ensure the success and the social acceptance of this research in the long term, it must now be a ethical framework created during the Ersatzhirne are still in the early stage of development.“ Ultimately, the key is to clarify what is acceptable or not acceptable, before someone goes in his zeal a step too far. That such occurrences alone of individual researchers, not least, shows the example of the Chinese, He Jiankui, the change in the genetic material of embryos with the Gene-scissors Crispr/Cas9 – although international research organisations are still debating whether a use is safe or ethical.

Organoids are not yet matured

as young as the Gene shears technology, so much so, the Organoid is breeding still in its infancy. "Organoids have been vessels neither blood nor immune cells," says Julia Ladewig. "Therefore, one tries to combine them with other systems." As long as the Organoid is not moved as normal tissue of the blood vessels with enough oxygen and other nutrients can be supplied, the inner cells of the tissue cluster under powered and die off quickly – one of the reasons why the Formations are not much bigger than a few Milli - or centimeters. In addition, the Lack of blood suggests that the Immune and other specialized cells that the brain organoids, in certain situations, behave differently than the model body.

fabric miniature breeding-and-nut cakes gives insight into the mother's womb

Nevertheless, the technique provides important insights. One reason for this is that the Organoids of the researchers can be selectively modified – for example, to the formation of brain tumors to understand better. The working group of Indians Verma from the Salk Institute for Biological Studies in La Jolla, California was recently a cancer-promoting Gene in some brain cells and destroyed at the same time a tumor suppressive Gene in their genome. The researchers used these cells in a brain organoid, developed within the shortest possible time, a more aggressive Tumor, and researchers were for the first time "live" in the Genesis of cancer and its spread. In addition, transplanted Verma and colleagues in cancer cells of brain tumor patients in the Organoids to study the behavior of – and so, in the future, perhaps the most appropriate therapy, the researchers write in the journal "Cell" and praise the "potential of organo-halides as a test platform for human cancer forms and the study of tumor development".