June 14 (UPI) -- Genetically engineered bacteria helped treat constipation in mice, according to a study.
Researchers at the Mayo Clinic Center for Individualized Medicine developed bacteria that produced large amounts of the chemical tryptamine, which helps food pass through the intestines with potentially less risk of side effects than other constipation drugs.
The scientists, who published their findings Wednesday in the journal Cell Host & Microbe, said clinical human trials won't be conducted for at least three years.
Probiotics, which are live bacteria that can aid in digestion, are not effective for everyone because the mix of bacteria found in the stomach and intestines is unique to each person. And changes in diet also don't always work because people's genes and microbiomes are different.
"These synthetic bacteria spur transit of food through the digestive system without messing with diet and microbes," lead author Dr. Purna Kashyap, associate director of the Center for Individualized Medicine Microbiome Program, said in a press release.
In the study, researchers found bacterially-produced tryptamine helps accelerate food through the digestive system in mice.
"Tryptamine is similar to the chemical serotonin, which is produced in our gut," Kashyap said. "In this study, we found tryptamine can activate a receptor in the mouse gut that normally responds to serotonin, causing increased secretion of fluid from the lining of the colon."
Then, bacteria can direct the colon to secrete water, with the tryptamine acting on a host receptor and accelerating the movement of food through the digestive system.
Because bacterially-produced tryptamine quickly degrades in the intestine and doesn't seem to increase in the bloodstream, the risk of side effects outside the gastrointestinal tract appear to be minimal, the researchers sad.
"Our goal with this research is to find treatments that act only in the GI tract without creating problems in other parts of the body," Kashyap said.
In addition to constipation, Kashyap believes the research can play a role in the study of other gastrointestinal disorders such as irritable bowel syndrome.