You may have heard of a pacemaker for improving function of a human heart, but have you ever considered one for bowel functions?
In a study published this week in Nature Communications, a group of researchers have uncovered a previously unknown process in the human digestive system. This discovery could lead to successful ‘pacemaker’ treatments for bowel disorders.
Science has been aware since the late 19th century that the human gut processed nutrition and eliminated waste by breaking down food in a mechanical way, called segmentation. It was always thought that nerves in the gut did all the work.
This research changes that understanding.
The research team – consisting of scientists at the University of Toronto’s Institute of Biomaterials & Biomedical Engineering (IBBME), McMaster University and Wuhan University in China – blocked off nerves in the gut using Tetrodotoxin, a powerful neurotoxin.
Originally, the team thought segmentation would cease once the nerves in the gut were blocked. To their surprise, this important action continued, prompting the researchers to dig deeper.
“There’s no question that the nerves are crucial,” said Professor Berj Bardakjian (ECE, IBBME), a contributing author of the study. “The thing is, it was thought to be the only effect.”
Led by the Huizinga lab at McMaster University, the team discovered that a layer of interstitial cells lining the gut, known as the interstitial cells of the Cajal (ICC) actually interacts with smooth muscle in the gut to create the segmentation action necessary to proper digestion via an oscillating action, action in the form of coupled biological clocks.
The discovery may lead to dramatically different outcomes for people who have difficulty absorbing nutrients, such as those with nerve damage in the gut, certain cancers, and even irritable bowel syndrome or Crohn’s disease.
“Now that we’ve made this discovery we can make models [of this process], and once we have those we can design devices to go in and deal with motility issues,” said Bardakjian, whose lab was responsible for making sense of the data retrieved from the other two research partners.
Bardakjian added that there was still work to do.
“To be fair, this discovery will only help with the segmentation action of the gut. The nerves will still be required to trigger the propulsion mechanism. But once we have a working device, nutrition can at least be absorbed. And, once that stage is complete, the next challenge would be to see how we can fix the propulsion mechanism.”
“The bottom line is,” he continues, “those cases that were helpless because the nerves in their gut were damaged can now face very different outcomes.”
