Applying a new method that is used mainly in stem-cell research and regenerative medicine, researchers from the Technical University of Munich have now devised a robust mini-intestine in the lab for molecular research.
They first isolated small pieces of intestine containing stem cells - in this case from mice.
In the next step, a nutrient solution in a test tube stimulated the stem cells to develop into an organ-like structure.
In just a few days, a spherical organoid was formed that measured 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," explained lead researcher Dr Tamara Zietek.
"The mini-intestines exhibit all the essential functions of a real intestine," he added.
Owing to its enormous surface area - comparable to that of a one-bedroom apartment - and the huge number of neurons it contains, the intestine is sometimes referred to as the abdominal brain.
In addition to absorbing nutrients from the foods we eat, it influences our immune status and metabolism.
With the help of sensors, specialized cells in the intestinal wall determine which hormones, if any, should be released into the bloodstream.
Overall, it acts as a highly sophisticated control centre.
The intestinal organoid can actively absorb nutrients and drugs, release hormones after activation by nutrients and transmit signals within the intestinal cells to control these processes.
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," the scientists added.
The next step will be to work with mini-intestines grown from human intestinal biopsy material.
"We are already in contact with a hospital that can provide the required research material," the authors noted in the article that appeared in the journal Scientific Reports of the Nature Publishing Group.