Surgeons Are Trying to Grow Baby Intestines from Stem Cells

​Stem cells are a potential building block for all kinds of neat stuff—most notably, human tissues that could offer hope for regenerative medicine.

But one team of researchers at the Children's Hospital Los Angeles have been focusing on a particular organ: the small intestine. Tracy Grikscheit is a paediatric surgeon and scientist at the hospital, and the lead author on a new paper detailing the lab's latest efforts to generate tissue-engineered small intestines—a small intestine grown from stem cells.

Previously, the researchers had engineered small intestines first from animal cells, followed by human. They just weren't sure those cells actually worked. But the new study confirms an important next step: functionality.

"When we first did that, we looked in just a very rough way to see if it looked like intestine," Grikscheit explained over the phone. "The great question was, is the tissue that we're growing actually really recapitulating all the important functions of human intestine?"

The intestine's job is more complex than you might think. Crucially, in addition to absorbing nutrients, it has to "play defense" and act as a barrier, Grikscheit explained. The team's latest study, published in the American Journal of Physiology: Gastrointestinal and Liver Physiology, drilled down into the details of the engineered intestine and found that it can in fact do these things.

"What's important about this study is it's not just taking pictures of the cells and saying ok, they're in the proper location," said Grikscheit. "We're actually also looking at the function, so we're showing that not only are the cells present that would for example absorb the sugar in your breakfast, but they actually are doing that job of absorbing sugar."

The reason Grikscheit and her team are so interested in the small intestine is to help babies that suffer from intestinal problems. As paediatric surgeons at the Children's Hospital, they often care for babies that do not have enough small intestine to absorb the nutrients needed, which can lead to intestinal failure. This lack of intestine can be caused by malformations at birth, such as gastroschisis or intestinal atresia, or a disease seen mostly in premature babies called necrotising enterocolitis, in which the tissue dies.

At the moment, transplant is an option—but it's tricky finding matching tissue that's suitable for a baby, and the procedure itself can be risky. As the baby grows up, he or she will continue to have to take immunosuppressant medication for life. "Usually by about five years, half of those grafts have failed," said Griksheit.

The beauty of engineered tissue, of course, is it can be made from the patient's own stem cells. As a result, you don't have the same issues with finding a donor or organ rejection. Additionally, Griksheit suggested that if a baby was having intestine removed to treat a condition, surgeons could potentially re-implant stem cells at the same—pre-empting intestinal failure.

However, applying this technique to human patients is still some way off; this latest study is still looking at engineered intestine on a scale too small for use in humans. But Griksheit's team has a grant from the California Institute for Regenerative Medicine to work towards clinical trials.

"Basically, now that we know that the tissue grows and functions, we need to make more of it, and we need to start scaling up," she said. They'll be engineering sequentially larger pieces of intestine in the hopes of having enough to replace all that a 3kg baby might lose.