Unique Microbial Signature Identified in Systemic Sclerosis

Pam Harrison

June 12, 2015

ROME — Patients with systemic sclerosis have a distinct colonic microbiome that might contribute to clinical manifestations of the disease, according to a new study.

"I see scleroderma patients exclusively in my practice, and gastrointestinal symptoms are sometimes the number one complaint," said Elizabeth Volkmann, MD, from the University of California at Los Angeles. "Patients often don't even feel comfortable disclosing these symptoms because they are so personal."

In their study, Dr Volkmann and her team "found that systemic sclerosis patients have an increased abundance of bacteria that are known to perpetuate inflammation in other autoimmune diseases, particularly in Crohn's disease, and a decreased abundance of commensal bacteria that protect against inflammation."

"These disease-associated organisms offer potential new targets for intervention," Dr Volkmann told Medscape Medical News here at the European League Against Rheumatism Congress 2015.

The team compared 17 patients with systemic sclerosis with 17 age- and sex-matched healthy control subjects.

Median age of the patients was 52 years, and median duration of disease was 6.6 years.

Mean total GIT 2.0 score — which assesses distension and bloating, fecal soilage and diarrhea, constipation, social functioning, and emotional well-being — was 0.7, indicating that the patients had moderate symptom severity.

 
These disease-associated organisms offer potential new targets for intervention.
 

Antibiotics and probiotics were withheld for at least 3 weeks. All patients then underwent colonoscopy, during which both the cecum and the sigmoid mucosa were sampled. The researchers used gene sequencing to determine which microorganisms populated these two regions of the colon.

"Species that were found in higher abundance in systemic sclerosis patients are considered to be more invasive bacteria," Dr Volkmann reported.

For example, Enterobacteriales and Fusobacterium were in greater abundance in both the cecum and sigmoid of patients with systemic sclerosis than in the control subjects.

Bifidobacterium and Lactobacillus — both thought to protect the gut from inflammation and usually found in lower abundance in patients with inflammatory bowel disease — were also in greater abundance in patients with systemic sclerosis. This was an unusual finding, Dr Volkmann said.

In contrast, commensal bacteria, such as Bacteroides and Faecalibacterium, were in lower abundance in both regions of the colon in patients with systemic sclerosis than in the control subjects.

"Interestingly, the gains and losses that we saw in bacteria species in systemic sclerosis patients somewhat overlap those seen in Crohn's disease," she added.

Distinct Microbiotic Signature

"What I'd like to do next," said Dr Volkmann, "is look at very early systemic sclerosis to see if these changes are there before patients develop very severe manifestations of the disease, and whether we could avert further disease progression by altering the microbiome."

She did not rule out the use of fecal transplantation to alter the colonic microbiome. "Fecal transplantation has been found to be highly effective in inflammatory bowel disease," she pointed out.

"As we do more and more studies on the microbiome — and this is the first one ever done in scleroderma — I think fecal transplantation is really the future," she told Medscape Medical News.

These findings are very interesting, said microbiome expert Dirk Elewaut, MD, from the University of Ghent in Belgium. However, whether the distinct microbiotic signature in the colon of patients with systemic sclerosis gives rise to or is the result of the disease still has to be clarified, he said.

"Systemic sclerosis is a disease in high need of new therapies," he told Medscape Medical News. "Although trials are now ongoing that really focus on the disease, I think the idea of changing the intestinal microbiome is an interesting one. There are ways of generating mixtures of artificial microbiomes that are more appealing than fecal transplantation, and probably safer, but we'll have to see."

Dr Volkmann and Dr Elewaut have disclosed no relevant financial relationships.

European League Against Rheumatism (EULAR) Congress 2015: Abstract OP0213. Presented June 12, 2015.

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