Mini-intestine grown in a test tube

Scientists have grown a mini-intestine just a quarter of a millimetre across in a test tube that exhibits functions of the human intestine and can be used for nutritional research.
A team from the Technical University of Munich (TUM) in Germany has shown for the first time how artificially grown mini-intestines can be used in nutritional and diabetic research.
Among their many functions, intestinal hormones, known as incretins, control blood glucose levels, appetite and fat metabolism.
Diabetics and obese individuals have already been successfully treated with drugs based on the mechanisms of action of these hormones.
However, still too little is known about the precise mechanism behind incretin release.

Applying a new method that is used mainly in stem-cell research and regenerative medicine, researchers have now devised a robust intestinal model for molecular research into incretin release in a test tube (in vitro).

To do so, they first isolate small pieces of intestine containing stem cells - in this case from mice. In the next step, a nutrient solution in a test tube stimulates the stem cells to develop into an organ-like structure.
In just a few days, a spherical organoid forms that measures just a quarter of a millimetre across and is suitable for use in research.
"The special thing about our scientific work on the intestinal organoid is that we can observe its inner workings," said Dr Tamara Zietek of the Department of Nutrition Physiology.

"The mini-intestines exhibit all the essential functions of a real intestine," Zietek said.
The intestinal organoid can actively absorb nutrients and drugs, release hormones after activation by nutrients, transmit signals within the intestinal cells to control these processes.
"Until now, it was not possible to investigate these processes in a single model, because conventional models are unsuitable for all these measurements," said Zietek.
In addition, once mini-intestines have been grown, researchers can work with them for months, because they can be replicated in the laboratory.
"This drastically reduces the number of experimental animals needed," Zietek added.
The study appears in the journal Scientific Reports.