Minyu Qian ^1,2 Jianxin Shi ^1,2 Dezhao Bi ² Zhuoya Zhang ² Cheng Tan ^2*

• ¹ Nanjing University of Chinese Medicine, Nanjing, China
• ² Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, Liaoning Province, China

Background: Growing evidence indicates a potential association between the gut microbiome and psoriasis. Nevertheless, the precise nature of these associations and whether they constitute causal relationships remain unclear.Method: A rigorous bidirectional two-sample Mendelian randomization study was undertaken to establish a putative causal link between gut microbiota and psoriasis.We drew upon publicly available datasets containing summary statistics from GWAS to accomplish this. Utilizing various analytical techniques, including inverse variance weighting, MR-Egger, weighted median, weighted model, and MR-PRESSO, we sought to validate the putative causal association between gut microbiota and psoriasis. A reverse Mendelian randomization analysis was conducted to further investigate the relationship.Result: After conducting a forward Mendelian randomization analysis, a causal relationship was established between 19 gut microbiota and psoriasis. Furthermore, the reverse MR study revealed causality between psoriasis and 13 gut microbiota.Notably, no substantial heterogeneity of instrumental variables or horizontal pleiotropy was observed. Conclusion: This research suggests a potential genetic association and causal nexus between gut microorganisms and psoriasis, indicating potential implications for the clinical management and therapy of psoriasis. Additional observational studies with a larger population sample size and animal model experiments are imperative to fully elucidate this association's underlying mechanisms..