Study of the Gut Microbiome in Patients with Psoriatic Arthritis.

Background: Gut dysbiosis may play a role in immune-mediated diseases, such as psoriasis. There is a growing interest in understanding microbiome influence, with speculations around the importance of an altered gut microbiome linked to the progression to psoriatic arthritis in psoriasis. The objective of this study is to study the gut microbiome in patients with severe psoriatic disease with or without psoriatic arthritis.

Methods: V3/V4 16S rRNA gene sequencing and bioinformatics analyses were performed with the total DNA extracted from the stool samples of 30 patients with psoriatic disease, 15 of whom had documented psoriatic arthritis.

Results: We found differences in gut microbiome composition in psoriatic arthritis patients when looking for relative and especially differential abundances. Bacteroidaceae family (P = .02), Bacteroides genus (P=.02), and Bacteroides uniformis (P=.03) were more abundant in psoriatic arthritis patients on differential abundance, adjusted for each taxonomic level. However, the present study did not show significant differences in alpha or beta diversity.

Conclusion: This study shows different patterns of gut microbiome composition in patients with psoriatic arthritis, with significant overexpression of the Bacteroides genus. This reinforces the microbiome as a field of interest in psoriasis. Nevertheless, it should be noted that some previously described findings related to lower diversity and different clustering between groups could not be demonstrated, probably due to the small number of patients. Additionally, it remains difficult to understand the magnitude of the gut microbiome influence. Is dysbiosis a cause or consequence of the disease? However, the microbiome deserves our attention, especially since it brings different opportunities for intervention through diet, prebiotics and probiotics, pretreatment analysis, prognosis, and even microbiome modulation and transplantation.