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Unique microbial signature observed in patients with systemic sclerosis
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Patients with systemic sclerosis had a combination of intestinal flora that was distinct from healthy control participants, according to research by Elizabeth Volkmann, MD, and colleagues presented at the European League Against Rheumatism Annual European Congress of Rheumatology.
“Our findings of microbial imbalances in patients with systemic sclerosis has tremendous implications for both the diagnosis and the treatment of this disabling autoimmune disease,” Volkmann said in a press release from the meeting. “In our cohort of patients, we found an abundance of bacteria that are known to perpetuate inflammation in other autoimmune diseases, such as inflammatory bowel disease, and we also found a decrease in commensal bacteria. These are bacteria that are thought to protect against inflammation in the gut.”
Elizabeth Volkmann
Seventeen patients with systemic sclerosis (SSc) underwent a colonoscopy to collected cecum and sigmoid mucosal lavage samples. Patients had a median age of 52.1 years, and 88% were women. The patients’ median disease duration was 7.1 years.
The UCLA Scleroderma Clinical Trial Consortium Gastrointestinal Tract 2.0 (GIT-2) scoring system was used to evaluate gastrointestinal dysfunction. Microbiota was analyzed using an Illumina HiSeq 2000 16S sequencing, and the Greengenes database was used to select operational taxonomic units. Unweighted UniFrac distances between samples were used to calculate similarity between samples with QIIME, and the UniFrac distance matrix was visualized through principal coordinate analysis. Additionally, bacterial phylotypes at the genus taxonomy level were identified using pairwise comparisons between samples from patients with SSc and healthy samples.
Analysis showed a high proportion of pathogenic Enterobacteriales and Fusobacterium and fewer of the commensal bacteria Bacteroides and Faecalibacterium in patients with SSc compared with the proportions found in healthy participants. Sigmoid and cecum Bifidobacterium were found in greater proportions in patients with SSC, which are usually found in lower numbers in patients with inflammatory bowel disease, according to the researchers.
“Although gastrointestinal tract dysfunction is a major cause of morbidity and mortality in patients, its etiology has always remained elusive,” Volkmann said in the release. “By identifying significant differences in bacteria — both in type and quantity — seen in the colons of healthy individuals and those with SSc, we hope to have pinpointed the exact changes in body ecology that may contribute to the clinical symptoms of this disease. We believe investigating this specific microbial signature further has the potential to lead to better diagnostic tools and treatment for a truly debilitating condition.”
Future works involves the exploration of the relationship between the results of the microbiotic analysis and results of the GIT-2 questionnaire, according to the researchers. – by Shirley Pulawski
Reference:
Volkmann E, et al. Paper #OP0213. Presented at: European League Against Rheumatism Annual European Congress of Rheumatology; June 10-13, 2015; Rome.
Disclosure: The researchers report no relevant financial disclosures.