The findings once again demonstrate the gut’s close relationship with the brain not only in everyday gastrointestinal functions but also in the onset of chronic conditions in which prebiotics such as dietary fibres or probiotics have shown effectiveness.
CFS is a debilitating illness that includes symptoms such as fatigue, muscle and/or joint paint, sore throat, headaches and unrefreshing sleep.
Individuals with CFS have frequently complained of gastrointestinal issues, including but not limited to irritable bowel syndrome (IBS)
Cornell University researchers not only found a range of biological markers of the disease but were able to correctly diagnosed CFS in 83% of patients via blood and stool samples.
“We observed that bacterial diversity was decreased in the CFS specimens compared to controls,” the authors noted. “In particular, a reduction in the relative abundance and diversity of members belonging to the Firmicutes phylum."
In addition a number of inflammatory microbial agents were found in the blood suggesting a leaky gut resulting from intestinal problems would allow bacteria to enter the blood. Bacteria in the blood will initiate an immune response which can worsen symptoms.
Cause or effect?
The methodology put forward could offer a non-invasive diagnosis and a step toward understanding the cause of the disease.
Part of the problem that continues to confound experts is whether the altered gut microbiome is a cause or a whether it is a consequence of disease.
The team enrolled 48 people diagnosed with CFS and 39 healthy to form the control group and asked them to provide stool and blood samples.
Using DNA sequencing technology, the team mapped areas of microbial DNA from the stool samples in order to identify particular bacterial species.
The reduction in anti-inflammatory bacterial species and therefore diversity in the gut of CFS patients was an observation also seen in those with Crohn's disease and ulcerative colitis.
Similar studies have identified the gastrointestinal tract of CFS patients as an environment that is conducive to inflammation.
This environment might cause damage to the intestinal epithelium, thus increasing bacteria movement — or microbial translocation (MT) — and triggering an inflammatory immune response.
“Our data supports the hypothesis of increased MT in the CFS group as evidenced by significantly raised levels of inflammatory markers such as lipopolysaccharide (LPS) in the blood,” the study remarked.
Increased gut permeability and increased LPS levels have been also described in patients with liver diseases, and in inflammatory bowel disease (IBD) suggesting that an activation of pro-inflammatory agents could be important for disease progression in CFS.
Published online ahead of print, DOI: 10.1186/s40168-016-0171-4
“Reduced diversity and altered composition of the gut microbiome in individuals with myalgic encephalomyelitis/chronic fatigue syndrome.”
Authors: Ludovic Giloteaux, Julia Goodrich, William Walters, Susan Levine, Ruth Ley and Maureen Hanson