Causal links between gut microbiota, plasma metabolites, and insomnia: Insights from Mendelian randomization.

MR analysis identified 10 gut microbiome taxa potentially associated with insomnia risk.

• GWAS data from 5959 individuals were used for gut microbiota analysis.
• Insomnia outcome data were obtained from Pan-UKB, GERA, and FinnGen, covering 9007 cases and 871,802 controls.
• Increased abundance of certain gut microbiomes, such as species CAG-145 sp000435615, was linked to a higher risk of insomnia.
• Participants for gut microbiota analysis had a mean age of 45.7 years (SD = 11.5).

MR analysis identified 35 plasma metabolites potentially associated with insomnia.

• GWAS data from 8299 individuals were used for plasma metabolite analysis.
• Participants for plasma metabolite analysis had a mean age of 63 years (range 45–85).
• Plasma metabolites were analyzed as potential mediators between gut microbiota and insomnia.
• The analysis used publicly accessible GWAS data.

The plasma metabolite 3-ethylcatechol sulphate significantly mediated the effects of gut microbiomes on insomnia risk.

• Mediation effects were computed using the product of coefficients approach.
• 3-ethylcatechol sulphate explained up to 31.49% of the total effect of gut microbiomes on insomnia.
• This mediation finding highlights a specific biochemical pathway linking gut microbiota to insomnia through the gut-brain axis.
• The mediation analysis connected identified bacterial taxa to insomnia outcomes via specific plasma metabolites.

The study employed Mendelian randomization to explore causal relationships between gut microbiota, plasma metabolites, and insomnia using publicly accessible GWAS data.

• Gut microbiota GWAS data came from 5959 individuals; plasma metabolite GWAS data came from 8299 individuals.
• Insomnia outcome data were sourced from three databases: Pan-UKB, GERA, and FinnGen, with 9007 cases and 871,802 controls.
• The MR design was used to minimize confounding and assess causal directionality.
• Mediation analysis used the product of coefficients approach to quantify the proportion of the total effect mediated by plasma metabolites.

The findings implicate the gut-brain axis as a relevant pathway through which gut microbiota influences insomnia risk via plasma metabolites.

• Specific gut microbiome taxa were linked to altered plasma metabolite levels that in turn affected insomnia risk.
• The authors suggest these findings 'may inform the development of therapeutic targets for managing sleep disorders.'
• 3-ethylcatechol sulphate was identified as a key mediating metabolite in this pathway.
• The study highlights the role of gut microbiota in influencing insomnia risk, mediated through specific plasma metabolites.