Psoriasis and gut microbiota: A Mendelian randomization study

In recent years, an increasing number of observational studies have revealed an association between gut microbiota composition and psoriasis patients. However, whether this association reflects a causal relationship remains unclear. This study aimed to identify the causal relationship between gut microbiota and psoriasis through relevant research. In order to determine whether gut microbiota and psoriasis are causally related, we conducted a Mendelian randomization analysis using summary statistics from genome-wide association studies (GWAS). As the exposure factor, we used summary statistics data from a GWAS study conducted by the MiBioGen Consortium, including 18,340 individuals with whole-genome gut microbiota composition, and data from the FinnGen GWAS study on psoriasis, including 9267 patients and 364,071 controls as the disease outcome. Two-sample Mendelian randomization analysis was subsequently performed with inverse variance weighted, MR-Egger and weighted median, while sensitivity analyses were conducted to address heterogeneity and horizontal pleiotropy. The IVW results confirmed the causal relationship between certain gut microbiota groups and psoriasis. Specifically, family Veillonellaceae (OR = 1.162, 95% CI: 1.038-1.301, p = 0.009), genus Candidatus Soleaferrea (OR = 1.123, 95% CI: 1.011-1.247, p = 0.030) and genus Eubacterium fissicatena group (OR = 0.831, 95% CI: 0.755-0.915, p = 0.00016) showed significant associations. Sensitivity analysis did not reveal any abnormalities in SNPs. Currently, we have found some causal relationship between the gut microbiota and psoriasis. However, the study needs further RCTs for further validation.