Gut dysbiosis in Ankylosing Spondylitis

Abstract

Abstract: Background: Ankylosing Spondylitis(AS) is an inflammatory disorder that primarily affects the spine and sacroiliac joints, causing discomfort, rigidity, and potential spinal fusion. The exact causes of AS are still unknown, but emerging evidence suggests a combination of genetic, environmental, and microbial influences, including gut dysbiosis - an imbalance in gut microbiota composition. This systematic review aims to consolidate evidence linking gut microbiota changes to AS. Method: A range of databases, including Pubmed, Scopus and Cochrane were used to identify the relevant research publications, adhering to PRISMA guidelines and the PECO framework. Results: Our review included 38 research articles with a total of 2,425 participants. We found variability in the presence of the HLA-B27 gene, with prevalence rates between 10% and 100% among AS patients. Most studies analyzed fecal samples using either 16S rRNA(25/38) or shotgun sequencing methods(8/38) or real-time polymerase chain reaction(qPCR)(2/38) to assess the gut microbiome composition in AS patients and controls. Specific bacterial species, including Prevotella, Dialister, Collinsella, and Ruminococcus gnavus, were consistently observed to be enriched in patients with AS, particularly in those with active disease or HLA-B27 status. In contrast, bacterials taxa such as Faecalibacterium prausnitzii, Blautia, Roseburia, and members of were frequently reported to be depleted, indicating a shift toward a pro-inflammatory gut microbial profile in AS. The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) ranged from 0.4 to 9.4, Ankylosing Spondylitis Disease Activity Score (ASDAS) from 1.65 to 3.5 and higher; and Bath Ankylosing Spondylitis Functional Index (BASFI) ranged from 0.6 to 4.1, indicating varied disease severity. A comparative analysis of gut microbiome profiles between AS patients and healthy controls revealed that specific bacterial communities were associated with disease activity. Studies investigating the effect of IL-17 inhibitors (2/38), TNF-alpha inhibitors (6/38) reported an improvement in gut microbiota composition...