The intestine is, in its essence, a tube surrounded by rings of smooth muscle that periodically undergo rhythmic, sequential contractions followed by relaxations. This squeezes food through the tube - a process called peristalsis. Along the way, the food gradually gets absorbed.
When I first walked over to Calvin Kuo's, MD, PhD, lab to see his post-doc Akifumi Ootani's, MD, PhD, celebrated gut-in-a-dish - a huge triumph after three decades of global scientific efforts - I imagined I'd find myself looking at something like a cobra undulating in a glorified Jello ring. (Apparently the illustrator for my Stanford Medicine article had the same idea.)
I was wrong. Once tiny bits of minced intestine, spurred on by Chef Ootani's special sauce, start to grow in culture, they assume the shape of hollow spheroids (I call them "gutballs"), which every now and then perform an act that can throw as seasoned a microscopist as Manuel Amieva, MD, PhD, for a loop:
When Ootani showed up, petri dish in hand, Amieva stuck it under a microscope and started focusing on one of the little spheroids, trying to get the best view for shooting some video footage of it. As he was looking through the lens, the gutball impulsively perpetrated peristalsis.
“I jumped back! This thing was alive. It scared me. Usually, cells move at a sluggish pace,” says Amieva. But not this thing. “Now I was hooked, because I realized that we were dealing with this little Frankenstein monster living in a petri dish.”
Those little Frankensteins are going to teach biologists a lot about the origins and prevention of colon cancer, the mechanisms of the diseases and benefits attributable to the trillions of microorganisms that reside in the human gut, and how intestinal stem cells do their job. With some luck, we may someday see the advent of artificial intestines to replace injured or defective ones.