New
research reveals differences in the gut microbiomes of people with
myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) compared to
those of healthy controls.
ME/CFS
is characterized by unexplained debilitating fatigue, cognitive
dysfunction, gastrointestinal disturbances, among other symptoms.
The
study dedicated to understanding the biology of the disease in order to
develop effective means to diagnose, treat and prevent it. Findings
appear in the journal Cell Host & Microbe.
The
researchers conducted metagenomic and metabolomic analyses of fecal
samples collected from geographically diverse cohort of 106 cases and 91
healthy controls. Results revealed differences in gut microbiome
diversity, abundances, functional biological pathways, and interactions
between bacteria. Cases and controls were matched for age, sex,
geography, and socioeconomic status.
Gut bacteria Faecalibacterium prausnitzii and Eubacterium rectale,
which are both normally abundant and health-promoting, were reduced in
ME/CFS participants. For both bacteria, researchers also found a
deficient microbial capacity for synthesizing butyrate, the main fuel
for the body’s colon cell, with ME/CFS. The abundance of Faecalibacterium prausnitzii was inversely associated with fatigue severity.
The only other species identified with reduced relative abundance in ME/CFS was C. secundus,
an acetate-producer, that could contribute to the net acetate
deficiency the researchers found in ME/CFS subjects. Acetate is used by
butyrate-producing bacteria to produce butyrate.
An additional nine species had increased relative abundance in ME/CFS compared to healthy controls, including C. bolteae which in other research has correlated with fatigue in multiple sclerosis. Another, R. gnavus, has been associated with inflammatory bowel disease.
“The
gut microbiome is a complex ecological community teeming with diverse
inter-species interactions that can be beneficial or harmful. Our
research finds that in people with ME/CFS, there can be extensive
rewiring of the networks of bacteria in this system,” says study senior
author.
“Understanding
the connection between ME/CFS and disturbances in the gut microbiome
may lead to ways to classify the disease and targets for therapeutic
trials,” adds co-author.
In a 2017 study,
scientists reported discovered abnormal levels of specific gut bacteria
related to ME/CFS in patients with and without concurrent irritable
bowel syndrome, IBS. A year later, another study identified
a constellation of metabolites related to ME/CFS, providing the ability
to predict whether or not someone has the disorder with a confidence of
84 percent.
In a 2015 study,
CII researchers identified distinct immune changes in patients
diagnosed with ME/CFS. These immune signatures represented the first
robust physical evidence that ME/CFS is a biological illness as opposed
to a psychological disorder, and the first evidence that the disease has
distinct stages. In a 2012 study, researchers ruled out a purported link between a mouse retrovirus called XMRV and ME/CFS.
https://www.cell.com/cell-host-microbe/fulltext/S1931-3128(23)00029-X
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