Improvement of the gut microbiota balance in patients with axial spondyloarthritis after one year of biological therapy

Abstract

Background Dysbiosis of the gut microbiota might be associated with the development and progression of axial spondyloarthritis (axSpA). Biological disease-modifying antirheumatic drugs (bDMARDs) effectively treat axSpA, but non-response to therapy remains a challenge that might be related to the gut microbiota. Objectives To explore the gut microbiota changes in patients with axSpA following one year of bDMARD treatment. Methods In an extension of the prospective German Spondyloarthritis Inception Cohort (GESPIC), patients with radiographic axSpA and high disease activity despite NSAID treatment were recruited prior to bDMARD therapy initiation. Assessments of disease activity and fecal samples were collected before treatment and one year after. The results were compared with individuals with chronic back pain where inflammatory disease was ruled out. Microbiota composition was analyzed using 16S rRNA gene sequencing and SILVA138 database profiling. Treatment response to bDMARDs was defined as improvement in ASDAS by at least 1.1 points. Results The analysis included 99 patients with axSpA and 63 controls, based on availability of clinical and microbiome data. Patients with axSpA had a mean age of 36.4 ± 10.4 years and 64.4% (64) were males. HLA-B27 prevalence was higher in patients with axSpA than in controls (89.9% vs 7.9%, respectively). TFM_2023 Valeria Rios Rodriguez 7 Alpha diversity and beta diversity moved toward resembling the control group posttreatment, though not significantly. At baseline, patients with axSpA were depleted in Lachnospiraceae taxa such as Blautia, Roseburia and Fusicatenibacter, and enriched in Collinsella compared to controls. After treatment, most taxa increased in abundance, particularly Blautia. Collinsella levels remained stable, while shifts in Prevotella and Bacteroides correlated with ASDAS change. Conclusions The gut microbiota composition of patients with axSpA changed and resembled closer controls after one year of treatment with bDMARDs. The persistent enrichment of Collinsella despite time and treatment suggests it potential role as a disease biomarker.