How does it work? CasarsaGuru/Getty

Gut tissue that is almost exactly like the real thing has been grown in the lab and successfully grafted into mice for the first time. The achievement brings us closer to growing gut tissue transplants, an advance that would benefit people with inflammatory bowel disease, Crohn’s disease and chronic constipation.

“I feel this is one of the most complex tissues to have been engineered,” says Jim Wells of Cincinnati Children’s Hospital Medical Center in Ohio. “It has the inner lining that does all the absorption of nutrients and secretion of digestive juices, fully functional muscles that propel the food through the gut, and nerves that control the pulsed muscle movement.”

Wells and his team made the intestinal tissue by converting either ordinary skin or white blood cells into a type of stem cell called induced pluripotent stem cells. By providing these with different nutrients and growth factors, they encouraged them to form basic intestinal tissue – something the team first achieved in 2010.


But this time the researchers went further – they also created nerve cells, and used these to wire-up their gut tissue. “Now we’ve included nerves, and this gives the tissue mechanical function so it can undergo peristalsis, the pulsating action that propels food through the gut,” says Wells.

Tissue transplants

The researchers found that the tissue they made could pulse both in the lab and when small patches of it were grafted into the kidneys of mice – a convenient part of the body for seeing whether tissue can survive inside an animal’s body.

The team hasn’t yet worked on making a blood supply for the tissue, nor immune cells to protect it. But they found that both of these were supplied by the mouse’s own body when transplanted, suggesting the same might happen if the tissue is transplanted into people.

Wells’s colleague Michael Helmrath is currently making and testing hollow tubes of the lab-grown intestine tissue. These are 2 centimetres long, but if they can extend them to 10 centimetres, they may make good transplants for babies who have short bowel syndrome. This condition can affect premature babies that catch a bowel infection that destroys parts of their intestine, leaving them without enough gut to digest food and grow healthily.

The hope is to grow tissue for transplant into adults too, although Wells warns that this will take several years. “The complexity of the tissue will demand much more work before it reaches prime time in patients,” he says. “But we will learn a lot about bowel disorders on the way.”

Gut disorders

“I’m convinced this is just the beginning, as we move from controlling the fate of single cells to forming functional structures,” says Harald Ott of Massachusetts General Hospital, who has grown kidney and forelimb tissues in the lab.

The fact that lab-grown gut tissue has its own nerves means it could be useful for studying constipation and diarrhoea. “These affect hundreds of millions of people,” says Wells. The tissue may also be useful for testing medicines for side effects such as constipation or diarrhoea. “These are one of the major off-target effects of drugs,” says Wells.

Ultimately, the research may help people with inflammatory bowel disease and Crohn’s disease, both of which are caused by the immune system attacking a person’s own gut tissue. Wells’s team is working on creating tissue that contains such renegade immune cells, so that they can then test how different types of food or gut bacteria may affect these conditions.

Journal reference: Nature Medicine, DOI: 10.1038/nm.4233