Researchers at The Saban Research Institute of Children's Hospital Los Angeles have successfully created a tissue-engineered small intestine in mice that replicates the intestinal structures of natural intestine - a necessary first step toward someday applying this regenerative medicine technique to humans.
Working in the laboratory, the research team took samples of intestinal tissue from mice. This tissue was comprised of the layers of the various cells that make up the intestine - including muscle cells and the cells that line the inside, known as epithelial cells. The investigators then transplanted that mixture of cells within the abdomen on biodegradable polymers or "scaffolding."
What the team wanted to happen did - new, engineered small intestines grew and had all of the cell types found in native intestine. Because the transplanted cells had carried a green label, the scientists could identify which cells had been provided - and all of the major components of the tissue-engineered intestine derived from the implanted cells. Critically, the new organs contained the most essential components of the originals.
The original paper is also available, for those who are interested. The normal caveats apply here - it's a promising advance for researchers to show that they can make lengths of intestine grow correctly inside a living mouse, using scaffolds seeded with cells. But bear in mind that this is only a demonstration: the new section of intestine isn't hooked up or being put under load. It'll be a few more years, I'd guess, before we see mice (or perhaps pigs) with tissue engineered and functional replacement small intestines.
If you'd like to learn more, I noticed an educational set of pages on the topic put up by the students at UCI:
In tissue engineering, there are two fundamentally different approaches that can be taken. The first is to replicate the organanatomically, with the expectation that the function of the engineered organ will therefore be the same. The second approach is simply to replicate its function. Researchers who aim to engineer intestine have adopted the anatomical approach with the key problems including the development of a muscular layer and neuronal innovation are major challenges to its success. On the other hand,if the aim is to develop an absorptive surface with neointestinal epithelium, it is possible to be more imaginative about how this can be achieved.