Disease Features and Gastrointestinal Microbial Composition in Patients with Systemic Sclerosis from Two Independent...

Area of Science:

• Microbiome research
• Gastroenterology
• Rheumatology

Background:

• Systemic sclerosis (SSc) is a complex autoimmune disease affecting connective tissues.
• Gastrointestinal (GI) symptoms are common in SSc patients, but the role of the gut microbiome is not fully understood.

Purpose of the Study:

• To investigate alterations in GI microbial composition in patients with SSc.
• To explore the relationship between SSc features and GI microbiota composition.
• To compare microbial profiles across two international SSc cohorts.

Main Methods:

• 16S ribosomal RNA sequencing of stool specimens from SSc patients and controls.
• Analysis of alpha and beta diversity to assess microbial community structure.
• Multivariate negative binomial models to identify differentially abundant microbial genera.

Main Results:

• Early SSc patients showed reduced commensal bacteria (e.g., Faecalibacterium) and increased pathobionts (e.g., Desulfovibrio).
• Disease duration, interstitial lung disease, small intestinal bacterial overgrowth, and immunosuppression were associated with altered gut microbial diversity.
• Specific pathobionts (e.g., Streptococcus) were more abundant in one SSc cohort compared to another, even after controlling for disease features.

Conclusions:

• Dysbiosis, characterized by microbial imbalances, is present in early systemic sclerosis.
• Specific SSc disease characteristics are independently associated with fecal microbial composition.
• Environmental factors and disease manifestations likely interact to shape the SSc gut microbiome.