Miniature stomachs are being grown in laboratories, allowing researchers to test experimental drugs for ulcers, cancers and other disorders.

Human stomachs are unlike those found in most other animals. Systems found in mice, flies and laboratory are distinct from those in people, preventing researchers from performing highly effective animal tests.

Pluripotent stem cells are capable of developing into any type of body cell, dictated by chemical signals from outside. Researchers utilized two varieties of stem cells in the study. One was from a group obtained from a human embryo 15 years ago. The other was developed from a skin cell taken from an adult.  

Cells were directed to form a definitive endoderm - a thin layer of cells, created early in the development of stomachs, pancreases, lungs and livers. New chemical signals, delivered by proteins, drive the formation of the foregut, a tube-like structure.

"That's where we introduce our special mojo to go from 2D to 3D. We're triggering what would normally happen during embryonic development, when embryos start kind of flat, and then roll up into a three-dimensional embryo," Jim Wells, a developmental biologist at the Cincinnati Children's Hospital, said.

Growth of three-dimensional human organs in the laboratory is a relatively new science. Little is known about how the human stomach forms during development in the womb. The team was required to try several approaches to learn how the organ formed.

Helicobacter pylori is a bacteria which can be dangerous to humans when it enters the body. However, the organism does not affect most laboratory test animals, making it difficult to test the effects of infection. This can lead to ulcers, or even cancer of the stomach. These new model stomachs could provide a test bed for a new generation of medicines to treat the condition. Early tests with H. pylori suggest the tiny structures are performing as expected.

Miniature human stomachs took roughly one month to grow. Technically, they are not organs, but organoids, tiny versions of organs, possessing similar structures. Full-sized stomachs contain two main sections - the body which contains acid, where food is digested, as well as the gastric antrum. That portion of the stomach manages the production of proteins, which regulate enzymes, as well as the production of acid. The organoid is made up of just the gastric antrum, although future development of the technique will focus on developing a complete model.

Cincinnati Children's Hospital researchers recently announced they grew small intestines in the laboratory, using stem cells. The technique was detailed in the journal Nature Medicine on October 19. 

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