The Causality between Gut Microbiome and Psoriasis Vulgaris: Insights from a Bi-Directional Two-Sample Mendelian Randomization Analysis

Abstract Aims Growing evidence have shown a significant relationship between gut microbiome and psoriasis vulgaris. But their causality has not been clarified. To investigate the causality and the direction and strength of the association between gut microbiome and psoriasis vulgaris, we performed an Mendelian randomization (MR) analysis. Methods We obtained the summary statistics of gut microbiome and psoriasis vulgaris from the published genome-wide association study. The inverse-variance weighted model was the main analytical model for determining causal association in our MR analysis and was followed by multiple sensitivity analyses and reverse MR analysis to validate the robustness of MR results. Results 7 bacterial taxa related to psoriasis vulgaris were detected by the current MR analysis. In specific, the genus Eubacterium Fissicatena [ P = 3.66×10 − 5 <(0.05/196)] was a risk factor for psoriasis vulgaris, whereas genus Alloprevotella ( P = 0.040), genus Gordonibacter ( P = 0.038), genus Lachnospira ( P = 0.020), genus Odoribacter( P = 0.024), genus Terrisporobacter ( P = 0.046), and phylum Actinobacteria ( P = 0.042) were associate with a lower risk of psoriasis vulgaris. The reverse MR analysis suggest no evidence of causal association from psoriasis vulgaris to gut microbiome. Conclusion We validated the causalities between gut microbiome and psoriasis vulgaris and brought innovative insights into the therapy of psoriasis vulgaris: targeted regulating intestinal bacterial taxon to prevent and treat psoriasis vulgaris.