The organoids were implanted into the kidney capsules of the mice. This is the tough protective layer of the kidney, and it provided a safe space and ample blood supply for the growing organ. After six weeks, the new intestines were larger than the mouse kidneys themselves -- and had replicated almost all of the tissues present in a human intestine, including those needed to digest food.
Researchers are hopeful that this marks progress toward growing on-demand tissues to replace intestines damaged by illnesses such as cancer and Crohn's disease. But it could take years for their work to move from mice to humans.