Working with gut stem cells from humans and mice, scientists from the Johns Hopkins Children’s Center and the University of Pittsburgh have successfully grown healthy intestine atop a 3-D scaffold made of a substance used in surgical sutures.
In a further step that takes their work well beyond proof of concept, researchers report their laboratory-created intestine successfully regenerated gut tissue in the colons of dogs with missing gut lining.
Researchers caution that a fully functioning replacement intestine for humans is far off, but they say their results have laid the critical groundwork to do so.
In an initial set of experiments reminiscent of a peanut butter-and-jelly sandwich technique, researchers took stem cells from the colons of babies undergoing intestinal surgeries and from mice, then added immune cells called macrophages, the body’s scavengers that seek out and engulf debris along with foreign and diseased cells. To this mix, they added cells called fibroblasts, whose function is to form collagen and other connective substances that bind tissues and organs together. The idea, the scientists say, was to create a mixture that closely mimics the natural composition of the gut.
In a final step, the investigators implanted pieces of the newly created intestine about 1.6 inches in length into the lower portion of dog colons lacking parts of their intestinal lining. For two months, the dogs underwent periodic colonoscopies and intestinal biopsies. Strikingly, the guts of dogs with implanted intestines healed completely within eight weeks. By contrast, dogs that didn’t get intestinal implants experienced continued inflammation and scarring of their guts.