Spondylitis and Microbiome Dysbiosis: Both Bacterial and Fungal

So  many interesting things to write about…so little time!

Last October, I wrote a post about spondyloarthropothies, which is a family of autoimmune diseases that affect the spine.  These include Ankylosing spondylitis, psoriatic arthritis, arthritis related to inflammatory bowel disease, reactive arthritis, and juvenile idiopathic arthritis.  There has been a suspicion for some years now that the gut biome was related to the onset and progression of these diseases.  As I emphasized in that post, while these diseases remain strangely unfamiliar to most people – as opposed to the well-recognized rheumatoid arthritis, multiple sclerosis, Parkinson’s disease, etc. –  at least 2.7 MILLION people suffer from these diseases in the USA alone, which is almost 3X the number of people that suffer from the way better known Parkinson’s disease alone,  for example!

I’ve thus kept an eye out for anything new, as you can imagine as I am quite sure I have readers who suffer from these illnesses, or know someone who does.  I was happy to see a newly published paper which took an in-depth look at the biome differences between those with Ankylosing spondylitis (AS), the best studied in this family of illnesses, and healthy controls.[i]  The results were fascinating.

The study included 22 patients with  AS and 16 healthy controls (HC).  They found major differences in the bacterial microbiomes between the two groups, including a “significant increase” in diversity in the AS group that included a nearly 3-fold increase in Proteobacteria and a decrease in Bacteroidetes species, including Prevotella.  The bacteria of the AS group, “…showed that the gut bacteria in AS patients expressed more abundant genes involved in human diseases….”  As I pointed out in that October post, “A 2007 study: patients with AS were given Moxifloxacin, an antibiotic that works against both Gram-positive and negative bacteria. The results ‘…have shown that AS patients treated with Moxifloxacin resulted in a significant and sustained improvement…Serum inflammatory markers were greatly reduced after 12 weeks.’” If these results hold up in further studies, i.e. the increased levels of disease-causing bacteria in the guts of those with AS, the improvements seen using an antibiotic actually make a whole lot of sense.

What really interested me even more though was this:  “…a more pronounced fungal dysbiosis than bacterial dysbiosis in AS patients was detected in this study.  We observed a significant decrease in the diversity of intestinal fungi in these patients….” The ratio of fungi to bacteria was also significantly decreased.  That is, there are proportionally way too many bacteria and too few fungi, in comparison to the healthy controls.  Seeing as these two kinds of organisms tend to keep each other balanced, it’s not surprising that this ratio is off, considering the high levels of bacteria found.  This study was the first time anyone has looked at this aspect of the human biome in sponylitis.

The results were so striking that the researchers flat out state that their findings “…suggest an alteration of the entire ecosystem in the guts of AS patients.”

Also of note:  the degree of mycobiome alterations coincided with disease severity:  “…the patients with level III and IV [i.e. more severe] damage in their spines had different fungal microbiota structure than patients with level II damage or healthy controls.”  They state, “These results suggested a possible role of the mycobiome in the development of AS.”

By the way, there was also a correlation between blood markers for inflammation (like C-reactive protein (CRP)) and fungal dysbiosis.  In fact, the scientists compared those undergoing treatment for AS (using the biologic medication, Enbrel, or using NSAIDS (non-steroidal anti-inflammatory medications)) to those newly diagnosed who had not as yet started treatment.  These anti-inflammatory treatments had “…profound effects on changing specific gut microbial and fungal groups, which may be associated with altered disease activities in AS patients…” That is, lowering inflammation levels via treatment seems to have a major effect on the composition of the gut biome.

Seems to me this is a pretty major step forward in spondyloarthritis research and almost more exciting to me, is to read a paper wherein more than just the bacterial content of the gut was taken into account.  I hope this becomes a trend as I am quite sure, similar dysbiotic issues are factors in other inflammatory diseases as well.


[i] Li, M, et. al. Altered bacterial-fungal interkingdom networks in the guts of Ankylosing Spondylitis patients. mSystems. 2019;4(2). DOI: 10.1128/mSystems.00176-18

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