New Research into the Mycobiome and the Development of Crohn’s Disease

The biome buzz of last week surround newly published research out of the University of Utah.[i]  You’ll remember from previous posts on this subject (see here and here as two examples) that the mycobiome appears to play a big role in the development of inflammatory bowel diseases.  This research may be another big step ahead on this front.

We all have mycobiomes, fungi that inhabit our intestinal tract, and ordinarily, they appear to be either harmless or beneficial.  However, we know that under certain circumstances, fungi can become extremely problematic, causing yeast infections that can actually be life-threatening.  Fungi too, under adverse conditions, can cause damage to the intestines that leads to IBD.  Ordinarily, a healthy immune system working with a healthy bacterial microbiome, can keep yeasts in check.  However, when something goes off balance, yeast can become essentially pathogenic.

Researchers at the University of Utah noted that a common blood test for diagnosing Crohn’s disease involves looking for antibodies to fungi.  They began to search for the source of those antibodies, and found that the most common yeast in the intestines, Candida albicans, elicited the strongest immune response (i.e. creation of the most antibodies).  Further investigation of this phenomenon led them to realize that actually, the antibodies were meant to attack an elongated fungal cell called hyphae:  specifically, the antibodies bound to a protein (adhesins) on the hyphae cells that help the yeast stick to surfaces and become invasive.  Hyphae are long, fine filaments that fungi use to invade tissues.

Testing this out in mice, the scientists populated one group of animals with normal Candida and another with the abnormal, hyphae Candida.  Sure enough, in the latter group, the yeast caused intestinal damage that looked just like Crohn’s.  Thus, they were able to conclude that a normal antibody response would destroy the pathogenic form of Candida, thereby protecting the host.

Candida albicans also cause vaginal yeast infections, and the Utah scientists determined that a vaccine that is being developed to treat that issue actually induces an immune reaction against those same adhesin proteins on the hyphae Candida.  When tested in mice that have been engineered to develop IBD, those that are given this vaccine are less likely to develop the disease.  The question that obviously needs answering is whether or not this vaccine might cure, at least lessen the severity of, IBD.  More than that, can this approach – manipulating the immune response – be used to treat other gut related ailments?  In this case, the immune reaction essentially improves the quality of Candida albicans, creating a competitive disadvantage to members of its invasive state – thereby greatly benefiting the benign “…rounded, budding state, which improves their survival in the gut.”  Essentially, the immune response is the primary factor in making our relationship with Candida a symbiotic one, where both parties benefit.  Says the lead researcher, “We aim to exploit interactions with commensal microbes and the host immune system to harness microbial products for therapies…”

While the vaccine has not as yet been tested in humans with IBD, it’s a really interesting concept.  I’ll definitively keep an eye out for updates in the future as they appear.

_________________________________________________

[i] https://healthcare.utah.edu/publicaffairs/news/2021/07/fungi-in-gut-health.php