Scientists grew mini human guts inside mice - Ars Technica

“The largest part of the immune system in humans is the GI tract, and our biggest exposure to the world is what we put in our mouth,” says Michael Helmrath, a pediatric surgeon at Cincinnati Children’s Hospital Medical Center who treats patients with intestinal diseases.

In search of a better method, last week Helmrath and his colleagues announced in the journal Nature Biotechnology that they had transplanted tiny, three-dimensional balls of human intestinal tissue into mice.

Scientists elsewhere are growing similar miniature replicas of other human organs— including the brain, lung, and liver—to better understand how they develop normally and how things go awry to give rise to disease.

So, adding the immune system is an important part of that,” says Pradipta Ghosh, director of the Humanoid Center of Research Excellence at the University of California San Diego School, which is developing human organoids to screen and test drugs.

At that point, the organoids had also formed human lymphoid follicles, or Peyer’s patches, important structures in the intestine that keep pathogens at bay by maintaining levels of healthy bacteria.

The Cincinnati researchers also hope their organoids could one day be used to treat people born with genetic defects that affect their digestive systems, or those who have lost intestinal function to cancer or inflammatory bowel diseases.