your gut The obvious job: it processes the food you eat. But it has another important function. It protects you from any bacteria, viruses, or allergens you ingest with that food. It’s a thing,” says Michael Helmrath, a pediatric surgeon at the Cincinnati Children’s Hospital Medical Center who treats patients with bowel disease. .
Sometimes this system malfunctions or does not develop properly, which can lead to gastrointestinal conditions such as ulcerative colitis, Crohn’s disease, and celiac disease. These are all on the rise around the world. Animals’ diets and immune systems are so different from ours that studying these conditions in animals doesn’t tell us much.
Seeking a better way, Helmrath and his colleagues published last week in the journal nature biotechnology They transplanted small three-dimensional spheres of human intestinal tissue into mice. A few weeks later, these spheres, known as organoids, developed key functions of the human immune system. This model can be used to mimic the human intestinal system without experimenting with diseased patients.
The experiment is a dramatic follow-up to 2010, when researchers at Cincinnati Children’s created the world’s first functioning intestinal organoids, but their first model was a simpler version in a lab dish. bottom. After a few years, they realized, Helmrath said, that they “needed to be more like human organizations.”
Scientists elsewhere have grown similar miniature replicas of other human organs, such as the brain, lungs and liver, to learn how they develop normally and how things can go wrong to cause disease. Organoids are also used as human avatars for drug testing. Because they contain human cells and exhibit the same structure and function as real organs, they are considered by some researchers to be a better stand-in than laboratory animals.
“When trying to create these platforms for testing drug efficacy and drug side effects in human tissue models, it’s very important to actually make sure that the drug is as close to and as complete as possible to the tissue in which it functions. Ultimately it will be our human body, so adding an immune system is an important part of that,” said Pradipta Ghosh, director of the Humanoid Research Center at the University of California, San Diego. increase. Gauche was not involved in the research.
To grow organoids, scientists started with induced pluripotent stem cells. Induced pluripotent stem cells are made from mature human cells taken from blood or skin. These have the ability to turn into all kinds of body tissue. By giving the stem cells a specific molecular cocktail, the team induced them to become enterocytes. After 28 days of growth in his dish, the cells formed spheres of tissue just a few millimeters in diameter.
The team carefully transplanted these spheres into mice that were genetically engineered to suppress their own immune systems so that the organoid tissue would not be rejected. (The researchers transplanted the intestinal organoids next to each mouse’s kidney, so they were not actually connected to the animal’s digestive tract.) To stimulate the organoids to generate human immune cells, previously mice were fed human umbilical cord blood.of stem cells that can be transformed into cells of interest
