Gut Microbiota Influence Host Metabolism and Immune Responses in Atopic Dermatitis: A Next-Generation...

Gut dysbiosis has been linked to immune imbalance in allergic diseases, but the underlying mechanisms remain unclear. We aimed to verify whether gut microbiota composition is associated with cellular, metabolic, and immune pathways in atopic dermatitis.

Fifty adults with atopic dermatitis and 25 sex- and age-matched healthy controls were enrolled. Gut microbiome composition was assessed using V3-V4 16S rRNA sequencing. Functional pathways were inferred from microbiome data using PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States).

Despite only subtle differences in microbiota composition between patients with atopic dermatitis and controls, PICRUSt analysis identified significant differences in 149 functional pathways. Key pathways enriched in atopic dermatitis involved signal transduction mediated by protein kinases, as well as carbohydrate and lipid metabolism. Downregulated pathways included those related to energy metabolism, amino acid and nucleotide metabolism, antigen processing, and innate immune responses. In patients with atopic dermatitis, microbial diversity increased with EASI scores and IgE levels, correlating with additional predicted functional shifts.

Our results suggest that even subtle structural differences in gut microbiota may exert significant functional effects in atopic dermatitis. Altered pathways could contribute to immune imbalance and impaired epidermal barrier function. These findings underscore the importance of incorporating functional analyses into future gut microbiota studies of atopic dermatitis to help identify therapeutic targets, including candidate probiotic strains for supplementation.