Beschreibung:
<jats:sec><jats:title>Background</jats:title><jats:p>Systemic sclerosis (SSc) is a complex and still unclear rare disease. Microbiota has recently emerged as an important environmental factor in SSc pathogenesis, either at gut, oral and skin level.</jats:p></jats:sec><jats:sec><jats:title>Objectives</jats:title><jats:p>To investigate the role of microbiota in SSc subsets, focusing on the skin-oral-gut microbiota axis and serum and fecal free fatty acids (FFA) profile.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>Twenty-six consecutive SSc patients (22 females) (mean disease duration (SD): 13 ± 6.91 yrs), classified according to the ACR/EULAR2013 criteria, were enrolled. Demographic, clinical and laboratory data were recorded. Gastrointestinal symptoms were investigated with UCLA GIT-2.0-questionnaire. Fecal, unstimulated saliva and superficial epidermal samples were collected. Microbiota was assessed through 16S ribosomal RNA Next Generation gene-sequencing analysis. Gas Cromatography-Mass Spettroscopy was used to measure FFAs in serum and fecal samples.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Thirteen patients had limited cutaneous SSc (lcSSc), 13 diffuse cutaneous (dcSSc). The two subsets displayed a different cutaneous and fecal microbiota profile. In detail, the class of cutaneous <jats:italic>Sphingobacteria</jats:italic> was significantly higher in lcSSc (p<0.05), while the phylum of <jats:italic>Lentisphaerae</jats:italic>, the family of <jats:italic>Victivallaceae</jats:italic> and the genus of <jats:italic>Victivallis</jats:italic> were significantly higher in fecal samples of lcSSc (all p<0.05). A significant increase of fecal propionic acid was observed in lcSSc patients (p<0.05). Moreover, all fecal medium-chain FAs and hexanoic acids were significantly higher in lcSSc (p<0.05 and p<0.001, respectively). The analysis of serum FFAs levels showed an increase of valeric and octanoic acids in lcSSc (both p<0.05). A negative correlation between UCLA-GIT-2.0 total score and fecal octanoic acid (rho=-0.61; p=0.03), and a positive correlation with serum propionic acid (rho=0.55; p=0.05) was found in lcSSc.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>Our findings show a different microbiota signature in the skin and gut, and a different FFAs profile in lcSSc and dcSSc. Such a differential regulation of microbiota composition and bacterial metabolite production suggests different dynamics of skin-oral-gut microbiota axis in SSc subsets. This data could be useful to develop personalized therapies targeting gastrointestinal and skin involvement.</jats:p></jats:sec><jats:sec><jats:title>Disclosure of Interests</jats:title><jats:p>None declared.</jats:p></jats:sec>