Gut microbiota analysis in systemic sclerosis according to disease characteristics and nutritional status.

OBJECTIVES:Systemic sclerosis (SSc) is a rare multi-organ disorder with a prominent gastrointestinal (GI) involvement. Altered gut microbiota is now considered a pivotal factor associated with the development of immune-mediated and inflammatory diseases. We performed a 16S ribosomal RNA (rRNA) gene-sequencing analysis of fecal microbiota in a cohort of SSc patients and matched healthy controls (HCs), with the aim to obtain some hints about a possible role of dysbiosis in the onset, progression, and severity of the disease. METHODS:We analysed stool samples from 63 SSc patients with different disease duration, phenotype, and nutritional status and from 17 HCs through 16S ribosomal RNA (rRNA) gene-sequencing. RESULTS:Microbial richness was lower for patients with long-standing disease. A similar observation was made for patients with diffuse cutaneous SSc (dsSSc) compared to those with limited variant (lcSSc) and for patients who reported a recent weight loss. Consistent with previous reports, we noted a deviation of the intestinal microbial composition in patients with SSc compared to HCs, with a greater expression of Lactobacillus and Streptococcus and a depletion of Sutterella. Nutritional status, assessed using BMI as a surrogate, appeared to have a marked impact on the gut microbiota, with overweight patients showing lower richness compared both to underweight and normal-BMI patients. CONCLUSIONS:Our findings expand the current knowledge of gut microbiota in SSc and could be useful to identify patients who would most benefit from treatments aimed at restoring the eu-biosis.