Microbes in flux
A new study of the microbes in patients with inflammatory bowel disease may help in the development of new ways to diagnose patients or track the effectiveness of treatment, according to Pacific Northwest National Laboratory.
The study indicated that the biggest difference between the populations of intestinal microbes in healthy patients and those with bowel disease is dramatic fluctuations in the microbial communities in ill people.
Results were published Monday in Nature Microbiology by authors who included Colin Brislawn and Janet Jansson of the Department of Energy’s national lab in Richland. The team included scientists from Sweden, Spain, Germany and the United States.
Every human has trillions of bacteria and other microbes living in their intestines, helping digest food and fight against harmful bacteria.
Scientists have known that patients with inflammatory bowel disease have differences in their intestinal microbes, including fewer beneficial microbes and a greater chance of carrying bacteria such as E. coli.
“Sometimes the differences are quite substantial,” Jansson said. “Our latest results show that patients affected by this condition also have a much less stable gut microbiome than healthy people.”
This was one of the largest studies to observe the intestinal microbiome over a period of time.
It’s important to know not just what microbes are present, but also to understand how the microbial community changes as patient’s symptoms improve or worsen over time.
Colin Brislawn, PNNL scientist
Researchers collected fecal samples every three months for up to two years from 137 people, including people without intestinal disease and those with ulcerative colitis and different types of Crohn’s disease.
Inflammatory bowel disease includes a range of illnesses, some potentially life threatening, in which the body’s immune system attacks microbes and causes symptoms such as diarrhea and abdominal pain.
Some bacteria disappeared almost completely at times in patients with inflammatory bowel disease, the study found. That rarely happened in the healthy people studied. Some ill patients had more than half of their microbiome displaced by other microbes in a matter of months.
“It’s important to know not just what microbes are present, but also to understand how the microbial community changes as patient’s symptoms improve or worsen over time,” said Brislawn, who contributed to the statistical analysis.
Manipulating the microbiome to match that of healthy patients might become a treatment strategy to keep patients in remission, said gastroenterologist Jonas Halfvarson of Örebro University in Sweden.
In other gut microbiome research at PNNL, scientists discovered that where both a person and the person’s mother were born may have a big effect on the makeup of the microbial community in your intestines.
Our finding could have some exciting implications for people’s health.
Janet Jansson, PNNL chief scientist for biology
Research done by scientists at PNNL and Berkeley National Laboratory in California studied the genes of mice to link them to the presence and abundance of specific gut microbes.
“We are starting to tease out the importance of different variables, like diet, genetics and the environment, on microbes in the gut,” Jansson said. “It turns out that early life history and genetics both play a role.”
Groups of mice were housed in facilities with different environments for the first four weeks of their lives to mimic hometowns.
A clear microbial signature formed related to where mice were raised, which carried over to the next generation. Researchers also found indications that moderate shifts in diet play a role in determining what functions microbes carry out in the gut.
“Our finding could have some exciting implications for people’s health,” Jansson said. “In the future, perhaps people could have designer diets, optimized according to their genes and their microbiome, to digest foods more effectively or to modulate their susceptibility to disease.”
The research was published in the journal Nature Microbiology, with PNNL’s Jansson, Young-Mo Kim and Thomas Metz among the authors.