Investigating the causal link between gut microbiota and dry age-related macular degeneration: a bidirectional...

To assess the causal link between 211 gut microbiota (GM) taxa and dry age-related macular degeneration (dAMD) risk.

Mendelian randomization using instrumental factors taken from a genome-wide association study (GWAS) were used. Inverse variance weighted (IVW) analysis and sensitivity analysis were performed on the FinnGen project, which included 5095 cases and 222 590 controls.

The IVW analysis showed substantial genus- and family-level relationships between GM taxa and dAMD risk. Specifically, the family Peptococcaceae (P=0.03), genus Bilophila (P=3.91×10^-3), genus Faecalibacterium (P=6.55×10^-3), and genus Roseburia (P=0.04) were linked to a higher risk of developing dAMD, while the genus Candidatus Soleaferrea (P=7.75×10^-4), genus Desulfovibrio (P=0.04) and genus Eubacterium ventriosum group (P=0.04) exhibited a protective effect against dAMD. No significant causal relationships were observed at higher taxonomic levels. Additionally, in the reverse IVW analysis, no meaningful causal effects of the 7 GM taxa.

These findings give support for the gut-retina axis participation in dAMD and shed light on putative underlying processes. Investigations on the connection between GM and dAMD have not yet revealed the underlying mechanism.