Acetate, a metabolite produced by gut microbiota, may play a role in the development of dermatographic and spontaneous urticaria, according to a recent study's exploratory findings.
In the study, published in Clinical, Cosmetic and Investigational Dermatology, investigators employed a Mendelian randomization and mediation analysis to examine the interactions between gut microbiota, short-chain fatty acids (SCFAs), and urticaria subtypes. Using genome-wide association study (GWAS) data, they aimed to identify causal relationships and investigate the potential role of SCFAs, particularly acetate, in these interactions.
The investigators used genetic variants, specifically single-nucleotide polymorphisms (SNPs), linked to gut microbiota, SCFAs, and urticaria—drawing from extensive GWAS datasets. The research included large sample sizes, primarily from patients who had European ancestry, with 3,269 cases and 212,464 controls for spontaneous urticaria, 844 cases and 212,464 controls for dermatographic urticaria, and 107 cases and 212,464 controls for temperature-triggered urticaria.
The investigators found associations between specific gut microbiota taxa and different urticaria subtypes. For instance, one taxon showed a negative association with dermatographic urticaria. For temperature-triggered urticaria, seven taxa were negatively associated and four were positively associated. In the case of spontaneous urticaria, four taxa were negatively associated and six showed positive associations. However, these associations did not retain statistical significance after Bonferroni correction.
The investigators provided specific examples, including acetate's impact on dermatographic urticaria, with an odds ratio of 0.64 (95% confidence interval [CI] = 0.49–0.84), and on spontaneous urticaria, with an odds ratio of 0.85 (95% CI = 0.75–0.97). Acetate was found to play a mediating role in different urticaria subtypes, showing a mediation effect of −21.7% for dermatographic urticaria and −23.7% for spontaneous urticaria.
The analysis suggested that acetate may be associated with the risk of urticaria through its effects on gut microbiota. Multivariate Mendelian randomization indicated that acetate may mediate effects on both dermatographic and spontaneous urticaria.
The findings, while preliminary, indicated that further research is warranted. This study provided data on the gut-skin axis and the role of SCFAs in immune responses related to urticaria, highlighting the potential therapeutic implications of SCFAs and gut microbiota in the management of urticaria.
The authors reported no conflicts of interest.
