Evaluating the gut microbiota alterations and their correlation with cytokine gene expression in patients with...

Ankylosing spondylitis (AS) is a common form of spondyloarthritis, recognized as a chronic autoimmune disorder with an unclear etiology. This study aimed to investigate changes in the intestinal microbiota, (Bifidobacterium sp., Bacteroides sp., Clostridium leptum, and Enterobacteriaceae) and to explore their relationship with cytokine gene expression in patients with AS attending a rheumatology clinic or admitted to the rheumatology ward of Imam Khomeini Hospital in Urmia, Iran.

This investigation involved a cohort of twenty patients diagnosed with AS alongside a control group of twenty healthy individuals matched for age and sex. Fecal specimens were collected to extract DNA, which was subsequently analyzed for the characterization of the gut microbiome via PCR and quantitative real-time PCR. Furthermore, RNA obtained from peripheral blood mononuclear cells was analyzed to quantify the expression of pro-inflammatory cytokines as well as anti-inflammatory cytokines using qPCR.

The analysis revealed that the bacterial load of Enterobacteriaceae, Bacteroides and Bifidobacterium were markedly elevated in the patients than in the control group (P < 0.05). The relative amount of TNF-α, IL-17F, IL-17 A, and INF-γ were significantly increased in patients group compared to controls (P < 0.05). But, the relative amount of TGF-β was significantly reduced in AS patients compared with controls (P = 0.03).

To conclude, an imbalance was observed in the dominant intestinal microbiota in AS patients, leading to a shift in the microbiota towards the production and secretion of inflammatory cytokines, as well as a reduction in anti-inflammatory cytokines, thereby playing a critical role in the pathogenesis of AS disease.