A study has found that a fungus found in certain foods such as cheese and processed meats can cause intestinal injuries in humans and mice with Crohn’s disease to fester and impeding healing.
These findings, from researchers at Washington University School of Medicine in St. Louis and the Cleveland Clinic, suggest that there is potentially a diet-based way to treat Crohn’s disease.
“We’re not suggesting that people stop eating cheese and processed meat; that would be going far beyond what we know right now,” said first author Umang Jain, PhD, an instructor in pathology & immunology at the School of Medicine. “What we know is that this foodborne fungus gets into inflamed, injured tissue and causes harm. We’re planning to perform a larger study in people to figure out if there’s a correlation between diet and the abundance of this fungus in the intestine. If so, it is possible dietary modulation could lower levels of the fungus and thereby reduce symptoms of Crohn’s disease.”
Crohn’s disease is driven by chronic inflammation in the gastrointestinal tract and immunosuppressive medication is the usual treatment. Crohn’s patients endure flare-ups where digestive tracts are dotted with inflamed, open sores that can persist for up to months.
To understand why intestinal ulcers heal so slowly in some people, the researchers studied mice with injured intestines. By sequencing microbial DNA at the site of injury, they discovered that the fungus Debaryomyces hansenii was abundant in wounds but not in uninjured parts of the intestine. D. hansenii can be found in all kinds of cheeses, as well as sausages, beer, wine and other fermented foods.
Introducing D. hansenii into mice with injured intestines slowed down the healing process, and eliminating the fungus with amphotericin B sped it up. In humans, the researchers discovered D. hansenii in seven out of seven of people with Crohn’s disease, and another analysis of Crohn’s patients found D. hansenii present but only in sites of injury and inflammation.
“If you look at stool samples from healthy people, this fungus is highly abundant,” Jain said. “It goes into your body and comes out again. But people with Crohn’s disease have a defect in the intestinal barrier that enables the fungus to get into the tissue and survive there. And then it makes itself at home in ulcers and sites of inflammation and prevents those areas from healing.”
Their results suggest that elimination of the fungus could allow wounds to heal normally again, and minimise flare-ups. In mouse studies, amphotericin B eliminated the fungus but it is of limited use in people since it can only be administered intravenously, therefore an oral antifungal is being researched.
“Crohn’s disease is fundamentally an inflammatory disease, so even if we figured out how to improve wound healing, we wouldn’t be curing the disease,” Jain said. “But in people with Crohn’s, impaired wound healing causes a lot of suffering. If we can show that depleting this fungus in people’s bodies—either by dietary changes or with antifungal medications—could improve wound healing, then it may affect the quality of life in ways that we’ve not been able to do with more traditional approaches.”
Source: Medical Xpress
Journal information: U. Jain et al., “Debaryomyces is enriched in Crohn’s disease intestinal tissue and impairs healing in mice,” Science (2021). science.sciencemag.org/cgi/doi … 1126/science.abd0919
