Dandruff may be a crucial factor in Crohn's disease: Scientists discover that hair follicle is also in the GOOD and causes inflammatory reactions in digestive diseases
- LA researchers discovered that the fungus, which is common in human hair follicles, lives in the gut
- In most cases it is harmless, but in some people with a specific genetic makeup it triggers a reaction
Mia De Graaf Health Editor for Dailymail.com
According to a new study, a dandruff-related fungus may be a major contributor to chronic Crohn's disease.
Malassezia yeasts in oily skin and scalp follicles are associated with skin conditions, including dandruff.
Researchers discovered that the fungus, which is commonly found in human hair follicles, also lives in the gut.
It is harmless in most of us, but some people with a certain genetic make-up seem to be aggravating their bowel disorders, such as inflammatory bowel disease (IBD).
The research team hopes that eliminating this fungus in people with Crohn's could alleviate some or all of their debilitating symptoms.
Researchers discovered that dandruff fungus lives in the intestines of many people, but in most cases does not trigger a response (left). Some people, however, suffer from inflammation (right)
David Underhill of Cedars Sinai Hospital in Los Angeles, co-author of the study, said, "We were surprised to find that Malassezia rrrica was more common on intestinal tissue surfaces in patients with Crohn's disease than in healthy people.
"In addition, the presence of Malassezia was associated with a common variation in a gene known to be important for immunity to fungi – a genetic signature more common in patients with Crohn's disease than in the healthy population."
IBD is characterized by changes in the immune response to the gut microbiota.
While most studies on the microbiome focus on bacteria, the team of Drs. Underhill the presence of fungi and their possible role in intestinal diseases.
Dr. Jose Limon, a member of the study's Cedars-Sinai research team, said that changes in intestinal fungi, such as M. resta – and fungal reactions – could be a factor in aggravating the symptoms that contribute to the disease in some patients with Crohn's disease ,
The researchers had originally discovered that fungi are present in the intestinal microbiota of mice and that immunity to fungi helps to control the intestinal inflammation.
In mice, the appearance of M. resta worsened colitis, a type of inflammatory bowel disease of the intestine.
Investigating the intestinal fungi of healthy people and patients with Crohn's disease, a form of IBD, researchers found several mucosa-associated fungi that were "significantly more common" in Crohn's disease.
The results published in the journal Cell Host and Microbe showed that, in particular, M. restrica was elevated in Crohn's patients carrying a genetic variation known as the IBD-CARD9 risk allele.
The researchers said the genetic variant enhances the ability of human immune cells to pump inflammatory cytokines in response to M. resta.
Dr. Underhill added, "The data so far does not indicate that Malassezia is inherently bad in the gut.
"We have found it in some healthy people, and in mice it does not seem to be a bowel disease.
"However, if it comes to an inflammation of the intestine, Malassezia seems to make it worse."
He said the next steps are to investigate whether eradicating yeast from the intestinal microbiome eliminates patient symptoms.